diff --git a/Dev/Plugin/Assets/Effekseer/Editor/EfkFileImporter.cs b/Dev/Plugin/Assets/Effekseer/Editor/EfkFileImporter.cs
index 424e7a5..435d5d7 100644
--- a/Dev/Plugin/Assets/Effekseer/Editor/EfkFileImporter.cs
+++ b/Dev/Plugin/Assets/Effekseer/Editor/EfkFileImporter.cs
@@ -1,4 +1,5 @@
-using System;
+#if UNITY_EDITOR
+using System;
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
@@ -145,3 +146,4 @@ private static void DisplayErrorDialog(string message)
 		}
 	}
 }
+#endif
\ No newline at end of file