diff --git a/Assets/UniRx/Scripts/UnityEngineBridge/Triggers/ObservableStateMachineTrigger.cs b/Assets/UniRx/Scripts/UnityEngineBridge/Triggers/ObservableStateMachineTrigger.cs
index f424a31a..e303bc18 100644
--- a/Assets/UniRx/Scripts/UnityEngineBridge/Triggers/ObservableStateMachineTrigger.cs
+++ b/Assets/UniRx/Scripts/UnityEngineBridge/Triggers/ObservableStateMachineTrigger.cs
@@ -1,11 +1,11 @@
 // over Unity5 added StateMachineBehaviour
 #if !(UNITY_4_6 || UNITY_4_5 || UNITY_4_4 || UNITY_4_3 || UNITY_4_2 || UNITY_4_1 || UNITY_4_0_1 || UNITY_4_0 || UNITY_3_5 || UNITY_3_4 || UNITY_3_3 || UNITY_3_2 || UNITY_3_1 || UNITY_3_0_0 || UNITY_3_0 || UNITY_2_6_1 || UNITY_2_6)
 
-using System;
 using UnityEngine;
 
-namespace UniRx
+namespace UniRx.Triggers
 {
+    [DisallowMultipleComponent]
     public class ObservableStateMachineTrigger : StateMachineBehaviour
     {
         public class OnStateInfo