diff --git a/render/jpql/src/main/kotlin/com/linecorp/kotlinjdsl/render/jpql/serializer/impl/JpqlFunctionSerializer.kt b/render/jpql/src/main/kotlin/com/linecorp/kotlinjdsl/render/jpql/serializer/impl/JpqlFunctionSerializer.kt
index 0c16d99f2..c7d7d7a62 100644
--- a/render/jpql/src/main/kotlin/com/linecorp/kotlinjdsl/render/jpql/serializer/impl/JpqlFunctionSerializer.kt
+++ b/render/jpql/src/main/kotlin/com/linecorp/kotlinjdsl/render/jpql/serializer/impl/JpqlFunctionSerializer.kt
@@ -21,7 +21,9 @@ class JpqlFunctionSerializer : JpqlSerializer<JpqlFunction<*>> {
         writer.write("FUNCTION")
 
         writer.writeParentheses {
+            writer.write("'")
             writer.write(part.name)
+            writer.write("'")
 
             if (IterableUtils.isNotEmpty(part.args)) {
                 writer.write(",")
diff --git a/render/jpql/src/test/kotlin/com/linecorp/kotlinjdsl/render/jpql/serializer/impl/JpqlFunctionSerializerTest.kt b/render/jpql/src/test/kotlin/com/linecorp/kotlinjdsl/render/jpql/serializer/impl/JpqlFunctionSerializerTest.kt
index 7658f3579..301de64bf 100644
--- a/render/jpql/src/test/kotlin/com/linecorp/kotlinjdsl/render/jpql/serializer/impl/JpqlFunctionSerializerTest.kt
+++ b/render/jpql/src/test/kotlin/com/linecorp/kotlinjdsl/render/jpql/serializer/impl/JpqlFunctionSerializerTest.kt
@@ -59,7 +59,9 @@ class JpqlFunctionSerializerTest : WithAssertions {
         verifySequence {
             writer.write("FUNCTION")
             writer.writeParentheses(any())
+            writer.write("'")
             writer.write(functionName1)
+            writer.write("'")
             writer.write(",")
             writer.write(" ")
             writer.writeEach(expressions, ", ", "", "", any())
@@ -86,7 +88,9 @@ class JpqlFunctionSerializerTest : WithAssertions {
         verifySequence {
             writer.write("FUNCTION")
             writer.writeParentheses(any())
+            writer.write("'")
             writer.write(functionName1)
+            writer.write("'")
         }
     }
 }