diff --git a/pom.xml b/pom.xml
index 925eca9a4..149e18083 100644
--- a/pom.xml
+++ b/pom.xml
@@ -1269,6 +1269,11 @@
 			<artifactId>corelib</artifactId>
 			<version>0.4.0</version>
 		</dependency>
+		<dependency>
+			<groupId>org.codelibs</groupId>
+			<artifactId>sai</artifactId>
+			<version>0.1.0-SNAPSHOT</version>
+		</dependency>
 		<dependency>
 			<groupId>org.codelibs</groupId>
 			<artifactId>curl4j</artifactId>
diff --git a/src/main/java/org/codelibs/fessexpression/engine/SaiExpressionEngine.java b/src/main/java/org/codelibs/fessexpression/engine/SaiExpressionEngine.java
new file mode 100644
index 000000000..065d3ad8f
--- /dev/null
+++ b/src/main/java/org/codelibs/fessexpression/engine/SaiExpressionEngine.java
@@ -0,0 +1,41 @@
+/*
+ * Copyright 2012-2019 CodeLibs Project and the Others.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
+ * either express or implied. See the License for the specific language
+ * governing permissions and limitations under the License.
+ */
+package org.codelibs.fessexpression.engine;
+
+import java.util.Map;
+
+import javax.script.ScriptEngine;
+import javax.script.ScriptException;
+
+import org.lastaflute.di.core.LaContainer;
+import org.lastaflute.di.core.expression.engine.JavaScriptExpressionEngine;
+
+public class SaiExpressionEngine extends JavaScriptExpressionEngine {
+    @Override
+    protected Object actuallyEvaluate(String exp, Map<String, ? extends Object> contextMap, LaContainer container, String firstName,
+            Object firstComponent) {
+        final ScriptEngine engine = prepareScriptEngineManager().getEngineByName("sai");
+        if (firstName != null) {
+            engine.put(firstName, firstComponent);
+        }
+        try {
+            return engine.eval(exp);
+        } catch (ScriptException | RuntimeException e) {
+            throwJavaScriptExpressionException(exp, contextMap, container, e);
+            return null; // unreachable
+        }
+    }
+}
diff --git a/src/main/resources/lasta_di.properties b/src/main/resources/lasta_di.properties
index c65e9325b..ee1c3cd6d 100644
--- a/src/main/resources/lasta_di.properties
+++ b/src/main/resources/lasta_di.properties
@@ -7,3 +7,6 @@ smart.deploy.mode.location = fess_env.properties: lasta_di.smart.deploy.mode
 
 # package for smart deploy target e.g. org.docksidestage.app
 smart.package1 = org.codelibs.fess.app
+
+# script engine
+dixml.script.expression.engine=org.codelibs.fessexpression.engine.SaiExpressionEngine