diff --git a/src/main/java/org/codelibs/fess/entity/PingResponse.java b/src/main/java/org/codelibs/fess/entity/PingResponse.java
index 2b5d47797..a6d63b76d 100644
--- a/src/main/java/org/codelibs/fess/entity/PingResponse.java
+++ b/src/main/java/org/codelibs/fess/entity/PingResponse.java
@@ -18,6 +18,7 @@ package org.codelibs.fess.entity;
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.OutputStream;
+import java.util.Locale;
 
 import org.apache.commons.text.StringEscapeUtils;
 import org.codelibs.core.lang.StringUtil;
@@ -28,6 +29,22 @@ import org.elasticsearch.cluster.health.ClusterHealthStatus;
 import org.elasticsearch.common.xcontent.XContentType;
 
 public class PingResponse {
+    private static final String CLUSTER_NAME = "cluster_name";
+    private static final String STATUS = "status";
+    private static final String TIMED_OUT = "timed_out";
+    private static final String NUMBER_OF_NODES = "number_of_nodes";
+    private static final String NUMBER_OF_DATA_NODES = "number_of_data_nodes";
+    private static final String NUMBER_OF_PENDING_TASKS = "number_of_pending_tasks";
+    private static final String NUMBER_OF_IN_FLIGHT_FETCH = "number_of_in_flight_fetch";
+    private static final String DELAYED_UNASSIGNED_SHARDS = "delayed_unassigned_shards";
+    private static final String TASK_MAX_WAIT_TIME_IN_QUEUE_IN_MILLIS = "task_max_waiting_in_queue_millis";
+    private static final String ACTIVE_SHARDS_PERCENT_AS_NUMBER = "active_shards_percent_as_number";
+    private static final String ACTIVE_PRIMARY_SHARDS = "active_primary_shards";
+    private static final String ACTIVE_SHARDS = "active_shards";
+    private static final String RELOCATING_SHARDS = "relocating_shards";
+    private static final String INITIALIZING_SHARDS = "initializing_shards";
+    private static final String UNASSIGNED_SHARDS = "unassigned_shards";
+
     private final int status;
 
     private final String clusterName;
@@ -40,7 +57,26 @@ public class PingResponse {
         status = response.getStatus() == ClusterHealthStatus.RED ? 1 : 0;
         clusterName = response.getClusterName();
         clusterStatus = response.getStatus().toString();
-        try (OutputStream out = EsUtil.getXContentOutputStream(response, XContentType.JSON)) {
+        try (OutputStream out = EsUtil.getXContentBuilderOutputStream((builder, params) -> {
+            builder.startObject();
+            builder.field(CLUSTER_NAME, response.getClusterName());
+            builder.field(STATUS, response.getStatus().name().toLowerCase(Locale.ROOT));
+            builder.field(TIMED_OUT, response.isTimedOut());
+            builder.field(NUMBER_OF_NODES, response.getNumberOfNodes());
+            builder.field(NUMBER_OF_DATA_NODES, response.getNumberOfDataNodes());
+            builder.field(ACTIVE_PRIMARY_SHARDS, response.getActivePrimaryShards());
+            builder.field(ACTIVE_SHARDS, response.getActiveShards());
+            builder.field(RELOCATING_SHARDS, response.getRelocatingShards());
+            builder.field(INITIALIZING_SHARDS, response.getInitializingShards());
+            builder.field(UNASSIGNED_SHARDS, response.getUnassignedShards());
+            builder.field(DELAYED_UNASSIGNED_SHARDS, response.getDelayedUnassignedShards());
+            builder.field(NUMBER_OF_PENDING_TASKS, response.getNumberOfPendingTasks());
+            builder.field(NUMBER_OF_IN_FLIGHT_FETCH, response.getNumberOfInFlightFetch());
+            builder.field(TASK_MAX_WAIT_TIME_IN_QUEUE_IN_MILLIS, response.getTaskMaxWaitingTime().getMillis());
+            builder.field(ACTIVE_SHARDS_PERCENT_AS_NUMBER, response.getActiveShardsPercent());
+            builder.endObject();
+            return builder;
+        }, XContentType.JSON)) {
             message = ((ByteArrayOutputStream) out).toString(Constants.UTF_8);
             if (StringUtil.isBlank(message)) {
                 message = "{}";
diff --git a/src/main/java/org/codelibs/fess/util/EsUtil.java b/src/main/java/org/codelibs/fess/util/EsUtil.java
index bea2bf3c4..f3982918e 100644
--- a/src/main/java/org/codelibs/fess/util/EsUtil.java
+++ b/src/main/java/org/codelibs/fess/util/EsUtil.java
@@ -33,8 +33,8 @@ public final class EsUtil {
     private EsUtil() {
     }
 
-    public static OutputStream getXContentOutputStream(final ToXContent xContent, final XContentType xContentType) {
-        try (final XContentBuilder builder = xContent.toXContent(XContentFactory.contentBuilder(xContentType), ToXContent.EMPTY_PARAMS)) {
+    public static OutputStream getXContentBuilderOutputStream(final XContentBuilderCallback func, final XContentType xContentType) {
+        try (final XContentBuilder builder = func.apply(XContentFactory.contentBuilder(xContentType), ToXContent.EMPTY_PARAMS)) {
             builder.flush();
             return builder.getOutputStream();
         } catch (final IOException e) {
@@ -44,4 +44,12 @@ public final class EsUtil {
             return new ByteArrayOutputStream();
         }
     }
+
+    public static OutputStream getXContentOutputStream(final ToXContent xContent, final XContentType xContentType) {
+        return getXContentBuilderOutputStream((builder, params) -> xContent.toXContent(builder, params), xContentType);
+    }
+
+    public interface XContentBuilderCallback {
+        XContentBuilder apply(XContentBuilder builder, ToXContent.Params params) throws IOException;
+    }
 }