diff --git a/src/main/java/org/codelibs/fess/rank/fusion/RankFusionProcessor.java b/src/main/java/org/codelibs/fess/rank/fusion/RankFusionProcessor.java
index 4293f3d6e..e22aa4fac 100644
--- a/src/main/java/org/codelibs/fess/rank/fusion/RankFusionProcessor.java
+++ b/src/main/java/org/codelibs/fess/rank/fusion/RankFusionProcessor.java
@@ -180,7 +180,7 @@ public class RankFusionProcessor implements AutoCloseable {
         final var docs = scoreDocMap.values().stream()
                 .sorted((e1, e2) -> Float.compare(toFloat(e2.get(scoreField)), toFloat(e1.get(scoreField)))).toList();
         int offset = 0;
-        for (int i = 0; i < windowSize / 2; i++) {
+        for (int i = 0; i < windowSize / 2 && i < docs.size(); i++) {
             if (!mainIdSet.contains(docs.get(i).get(idField))) {
                 offset++;
             }
@@ -193,9 +193,24 @@ public class RankFusionProcessor implements AutoCloseable {
         if (Relation.EQUAL_TO.toString().equals(mainResult.getAllRecordCountRelation())) {
             allRecordCount += offset;
         }
-        return createResponseList(docs.subList(startPosition, startPosition + pageSize), allRecordCount,
-                mainResult.getAllRecordCountRelation(), mainResult.getQueryTime(), mainResult.isPartialResults(),
-                mainResult.getFacetResponse(), startPosition, pageSize, offset);
+        return createResponseList(extractList(docs, pageSize, startPosition), allRecordCount, mainResult.getAllRecordCountRelation(),
+                mainResult.getQueryTime(), mainResult.isPartialResults(), mainResult.getFacetResponse(), startPosition, pageSize, offset);
+    }
+
+    protected List<Map<String, Object>> extractList(final List<Map<String, Object>> docs, final int pageSize, final int startPosition) {
+        final int size = docs.size();
+        if (size == 0) {
+            return docs; // empty
+        }
+        int fromIndex = startPosition;
+        if (fromIndex >= size) {
+            fromIndex = size - 1;
+        }
+        int toIndex = startPosition + pageSize;
+        if (toIndex >= size) {
+            toIndex = size;
+        }
+        return docs.subList(fromIndex, toIndex);
     }
 
     protected List<Map<String, Object>> searchWithMainSearcher(final String query, final SearchRequestParams params,
diff --git a/src/main/java/org/codelibs/fess/rank/fusion/SearchResult.java b/src/main/java/org/codelibs/fess/rank/fusion/SearchResult.java
index c322c9973..406461c6e 100644
--- a/src/main/java/org/codelibs/fess/rank/fusion/SearchResult.java
+++ b/src/main/java/org/codelibs/fess/rank/fusion/SearchResult.java
@@ -69,6 +69,13 @@ public class SearchResult {
         return new SearchResultBuilder();
     }
 
+    @Override
+    public String toString() {
+        return "SearchResult [documentList=" + documentList + ", allRecordCount=" + allRecordCount + ", allRecordCountRelation="
+                + allRecordCountRelation + ", queryTime=" + queryTime + ", partialResults=" + partialResults + ", facetResponse="
+                + facetResponse + "]";
+    }
+
     static class SearchResultBuilder {
 
         private long allRecordCount;
diff --git a/src/test/java/org/codelibs/fess/rank/fusion/RankFusionProcessorTest.java b/src/test/java/org/codelibs/fess/rank/fusion/RankFusionProcessorTest.java
index f348e5858..25bb1f71b 100644
--- a/src/test/java/org/codelibs/fess/rank/fusion/RankFusionProcessorTest.java
+++ b/src/test/java/org/codelibs/fess/rank/fusion/RankFusionProcessorTest.java
@@ -95,7 +95,7 @@ public class RankFusionProcessorTest extends UnitFessTestCase {
         }
     }
 
-    public void test_1searcher10_1000docs_100size() throws Exception {
+    public void test_1searcher10_45_45_1000docs_100size() throws Exception {
         String query = "*";
         int allRecordCount = 1000;
         int pageSize = 100;
@@ -191,7 +191,7 @@ public class RankFusionProcessorTest extends UnitFessTestCase {
 
             if (rankFusionProcessor.search(query, new TestSearchRequestParams(1000, pageSize, offset),
                     OptionalThing.empty()) instanceof QueryResponseList list) {
-                assertEquals(pageSize, list.size());
+                assertEquals(offset, list.size());
                 assertEquals(allRecordCount + offset, list.getAllRecordCount());
                 assertEquals(11, list.getAllPageCount());
                 assertEquals(1045, list.getCurrentEndRecordNumber());
@@ -208,6 +208,249 @@ public class RankFusionProcessorTest extends UnitFessTestCase {
         }
     }
 
+    public void test_1searcher0_0docs_100size() throws Exception {
+        String query = "*";
+        int allRecordCount = 0;
+        int pageSize = 100;
+        int offset = 0;
+        try (RankFusionProcessor rankFusionProcessor = new RankFusionProcessor()) {
+            rankFusionProcessor.setSeacher(new TestMainSearcher(allRecordCount));
+            rankFusionProcessor.register(new TestSubSearcher(0, 0, 0));
+            rankFusionProcessor.init();
+
+            if (rankFusionProcessor.search(query, new TestSearchRequestParams(0, pageSize, 0),
+                    OptionalThing.empty()) instanceof QueryResponseList list) {
+                assertEquals(0, list.size());
+                assertEquals(0, list.getAllRecordCount());
+                assertEquals(1, list.getAllPageCount());
+                assertEquals(0, list.getCurrentEndRecordNumber());
+                assertEquals(1, list.getCurrentPageNumber());
+                assertEquals(0, list.getCurrentStartRecordNumber());
+                assertEquals(offset, list.getOffset());
+                assertEquals(100, list.getPageSize());
+                assertEquals(0, list.getStart());
+            } else {
+                fail();
+            }
+        }
+    }
+
+    public void test_1searcher0_10docs_100size() throws Exception {
+        String query = "*";
+        int allRecordCount = 10;
+        int pageSize = 100;
+        int offset = 0;
+        try (RankFusionProcessor rankFusionProcessor = new RankFusionProcessor()) {
+            rankFusionProcessor.setSeacher(new TestMainSearcher(allRecordCount));
+            rankFusionProcessor.register(new TestSubSearcher(0, 0, 0));
+            rankFusionProcessor.init();
+
+            if (rankFusionProcessor.search(query, new TestSearchRequestParams(0, pageSize, 0),
+                    OptionalThing.empty()) instanceof QueryResponseList list) {
+                assertEquals(10, list.size());
+                assertEquals(10, list.getAllRecordCount());
+                assertEquals(1, list.getAllPageCount());
+                assertEquals(10, list.getCurrentEndRecordNumber());
+                assertEquals(1, list.getCurrentPageNumber());
+                assertEquals(1, list.getCurrentStartRecordNumber());
+                assertEquals(offset, list.getOffset());
+                assertEquals(100, list.getPageSize());
+                assertEquals(0, list.getStart());
+            } else {
+                fail();
+            }
+        }
+    }
+
+    public void test_1searcher0_1000docs_100size() throws Exception {
+        String query = "*";
+        int allRecordCount = 1000;
+        int pageSize = 100;
+        int offset = 0;
+        try (RankFusionProcessor rankFusionProcessor = new RankFusionProcessor()) {
+            rankFusionProcessor.setSeacher(new TestMainSearcher(allRecordCount));
+            rankFusionProcessor.register(new TestSubSearcher(0, 0, 0));
+            rankFusionProcessor.init();
+
+            if (rankFusionProcessor.search(query, new TestSearchRequestParams(0, pageSize, 0),
+                    OptionalThing.empty()) instanceof QueryResponseList list) {
+                assertEquals(pageSize, list.size());
+                assertEquals(1000, list.getAllRecordCount());
+                assertEquals(10, list.getAllPageCount());
+                assertEquals(100, list.getCurrentEndRecordNumber());
+                assertEquals(1, list.getCurrentPageNumber());
+                assertEquals(1, list.getCurrentStartRecordNumber());
+                assertEquals(offset, list.getOffset());
+                assertEquals(100, list.getPageSize());
+                assertEquals(0, list.getStart());
+            } else {
+                fail();
+            }
+        }
+    }
+
+    public void test_1searcher10_0docs_100size() throws Exception {
+        String query = "*";
+        int allRecordCount = 0;
+        int pageSize = 100;
+        int offset = 10;
+        try (RankFusionProcessor rankFusionProcessor = new RankFusionProcessor()) {
+            rankFusionProcessor.setSeacher(new TestMainSearcher(allRecordCount));
+            rankFusionProcessor.register(new TestSubSearcher(10, 0, 0));
+            rankFusionProcessor.init();
+
+            if (rankFusionProcessor.search(query, new TestSearchRequestParams(0, pageSize, 0),
+                    OptionalThing.empty()) instanceof QueryResponseList list) {
+                assertEquals(10, list.size());
+                assertEquals(10, list.getAllRecordCount());
+                assertEquals(1, list.getAllPageCount());
+                assertEquals(10, list.getCurrentEndRecordNumber());
+                assertEquals(1, list.getCurrentPageNumber());
+                assertEquals(1, list.getCurrentStartRecordNumber());
+                assertEquals(offset, list.getOffset());
+                assertEquals(100, list.getPageSize());
+                assertEquals(0, list.getStart());
+            } else {
+                fail();
+            }
+        }
+    }
+
+    public void test_1searcher10_10docs_100size() throws Exception {
+        String query = "*";
+        int allRecordCount = 10;
+        int pageSize = 100;
+        int offset = 0;
+        try (RankFusionProcessor rankFusionProcessor = new RankFusionProcessor()) {
+            rankFusionProcessor.setSeacher(new TestMainSearcher(allRecordCount));
+            rankFusionProcessor.register(new TestSubSearcher(10, 0, 0));
+            rankFusionProcessor.init();
+
+            if (rankFusionProcessor.search(query, new TestSearchRequestParams(0, pageSize, 0),
+                    OptionalThing.empty()) instanceof QueryResponseList list) {
+                assertEquals(10, list.size());
+                assertEquals(10, list.getAllRecordCount());
+                assertEquals(1, list.getAllPageCount());
+                assertEquals(10, list.getCurrentEndRecordNumber());
+                assertEquals(1, list.getCurrentPageNumber());
+                assertEquals(1, list.getCurrentStartRecordNumber());
+                assertEquals(offset, list.getOffset());
+                assertEquals(100, list.getPageSize());
+                assertEquals(0, list.getStart());
+            } else {
+                fail();
+            }
+        }
+    }
+
+    public void test_1searcher10_1000docs_100size() throws Exception {
+        String query = "*";
+        int allRecordCount = 1000;
+        int pageSize = 100;
+        int offset = 0;
+        try (RankFusionProcessor rankFusionProcessor = new RankFusionProcessor()) {
+            rankFusionProcessor.setSeacher(new TestMainSearcher(allRecordCount));
+            rankFusionProcessor.register(new TestSubSearcher(10, 0, 0));
+            rankFusionProcessor.init();
+
+            if (rankFusionProcessor.search(query, new TestSearchRequestParams(0, pageSize, 0),
+                    OptionalThing.empty()) instanceof QueryResponseList list) {
+                assertEquals(pageSize, list.size());
+                assertEquals(1000, list.getAllRecordCount());
+                assertEquals(10, list.getAllPageCount());
+                assertEquals(100, list.getCurrentEndRecordNumber());
+                assertEquals(1, list.getCurrentPageNumber());
+                assertEquals(1, list.getCurrentStartRecordNumber());
+                assertEquals(offset, list.getOffset());
+                assertEquals(100, list.getPageSize());
+                assertEquals(0, list.getStart());
+            } else {
+                fail();
+            }
+        }
+    }
+
+    public void test_1searcher1000_0docs_100size() throws Exception {
+        String query = "*";
+        int allRecordCount = 0;
+        int pageSize = 100;
+        int offset = 100;
+        try (RankFusionProcessor rankFusionProcessor = new RankFusionProcessor()) {
+            rankFusionProcessor.setSeacher(new TestMainSearcher(allRecordCount));
+            rankFusionProcessor.register(new TestSubSearcher(0, 0, 1000));
+            rankFusionProcessor.init();
+
+            if (rankFusionProcessor.search(query, new TestSearchRequestParams(0, pageSize, 0),
+                    OptionalThing.empty()) instanceof QueryResponseList list) {
+                assertEquals(pageSize, list.size());
+                assertEquals(100, list.getAllRecordCount());
+                assertEquals(1, list.getAllPageCount());
+                assertEquals(100, list.getCurrentEndRecordNumber());
+                assertEquals(1, list.getCurrentPageNumber());
+                assertEquals(1, list.getCurrentStartRecordNumber());
+                assertEquals(offset, list.getOffset());
+                assertEquals(100, list.getPageSize());
+                assertEquals(0, list.getStart());
+            } else {
+                fail();
+            }
+        }
+    }
+
+    public void test_1searcher1000_10docs_100size() throws Exception {
+        String query = "*";
+        int allRecordCount = 10;
+        int pageSize = 100;
+        int offset = 90;
+        try (RankFusionProcessor rankFusionProcessor = new RankFusionProcessor()) {
+            rankFusionProcessor.setSeacher(new TestMainSearcher(allRecordCount));
+            rankFusionProcessor.register(new TestSubSearcher(0, 0, 1000));
+            rankFusionProcessor.init();
+
+            if (rankFusionProcessor.search(query, new TestSearchRequestParams(0, pageSize, 0),
+                    OptionalThing.empty()) instanceof QueryResponseList list) {
+                assertEquals(pageSize, list.size());
+                assertEquals(100, list.getAllRecordCount());
+                assertEquals(1, list.getAllPageCount());
+                assertEquals(100, list.getCurrentEndRecordNumber());
+                assertEquals(1, list.getCurrentPageNumber());
+                assertEquals(1, list.getCurrentStartRecordNumber());
+                assertEquals(offset, list.getOffset());
+                assertEquals(100, list.getPageSize());
+                assertEquals(0, list.getStart());
+            } else {
+                fail();
+            }
+        }
+    }
+
+    public void test_1searcher1000_1000docs_100size() throws Exception {
+        String query = "*";
+        int allRecordCount = 1000;
+        int pageSize = 100;
+        int offset = 50;
+        try (RankFusionProcessor rankFusionProcessor = new RankFusionProcessor()) {
+            rankFusionProcessor.setSeacher(new TestMainSearcher(allRecordCount));
+            rankFusionProcessor.register(new TestSubSearcher(0, 0, 1000));
+            rankFusionProcessor.init();
+
+            if (rankFusionProcessor.search(query, new TestSearchRequestParams(0, pageSize, 0),
+                    OptionalThing.empty()) instanceof QueryResponseList list) {
+                assertEquals(pageSize, list.size());
+                assertEquals(1050, list.getAllRecordCount());
+                assertEquals(11, list.getAllPageCount());
+                assertEquals(100, list.getCurrentEndRecordNumber());
+                assertEquals(1, list.getCurrentPageNumber());
+                assertEquals(1, list.getCurrentStartRecordNumber());
+                assertEquals(offset, list.getOffset());
+                assertEquals(100, list.getPageSize());
+                assertEquals(0, list.getStart());
+            } else {
+                fail();
+            }
+        }
+    }
+
     static class TestMainSearcher extends RankFusionSearcher {
 
         private long allRecordCount;
@@ -221,7 +464,7 @@ public class RankFusionProcessorTest extends UnitFessTestCase {
             int start = params.getStartPosition();
             int size = params.getPageSize();
             SearchResultBuilder builder = SearchResult.create();
-            for (int i = start; i < start + size; i++) {
+            for (int i = start; i < start + size && i < allRecordCount; i++) {
                 Map<String, Object> doc = new HashMap<>();
                 doc.put(ID_FIELD, Integer.toString(i));
                 doc.put("score", 1.0f / (i + 1));