diff --git a/popcorn/Assets/MyGame/Prefabs/TutorialObjectMask.prefab b/popcorn/Assets/MyGame/Prefabs/TutorialObjectMask.prefab
index d221030e..5746c2a5 100644
--- a/popcorn/Assets/MyGame/Prefabs/TutorialObjectMask.prefab
+++ b/popcorn/Assets/MyGame/Prefabs/TutorialObjectMask.prefab
@@ -178,6 +178,7 @@ MonoBehaviour:
   unmask: {fileID: 4293843007976718248}
   unmaskArrow: {fileID: 5618796564699367770}
   unMaskImage: {fileID: 4293843007976718250}
+  backgroundImage: {fileID: 4293843007207798080}
   arrowAnimator: {fileID: 7626766843417898212}
 --- !u!223 &1057350325820014940
 Canvas:
diff --git a/popcorn/Assets/MyGame/Scenes/CornField/Scripts/CornField.cs b/popcorn/Assets/MyGame/Scenes/CornField/Scripts/CornField.cs
index e921bcd1..501f0bd6 100644
--- a/popcorn/Assets/MyGame/Scenes/CornField/Scripts/CornField.cs
+++ b/popcorn/Assets/MyGame/Scenes/CornField/Scripts/CornField.cs
@@ -319,6 +319,9 @@ public class CornField : MonoBehaviour
                 .Take(3)
                 .Subscribe(_ => { }, () =>
                 {
+                    // マスクの透明度変更
+                    cornFieldMask.SetBGAlpha(0f);
+                    cornFieldMask.SetArrowActive(false);
                     this.CallWaitForSeconds(4f, () =>
                     {
                         cornFieldMask.gameObject.SetActive(false);
diff --git a/popcorn/Assets/MyGame/Scripts/TutorialObjectMask.cs b/popcorn/Assets/MyGame/Scripts/TutorialObjectMask.cs
index 989691a2..a820d3a3 100644
--- a/popcorn/Assets/MyGame/Scripts/TutorialObjectMask.cs
+++ b/popcorn/Assets/MyGame/Scripts/TutorialObjectMask.cs
@@ -9,6 +9,7 @@ namespace MyGame.Scripts
         [SerializeField] private Unmask unmask;
         [SerializeField] private Unmask unmaskArrow;
         [SerializeField] private Image unMaskImage;
+        [SerializeField] private Image backgroundImage;
         [SerializeField] private Animator arrowAnimator;
         private static readonly int Under = Animator.StringToHash("Under");
 
@@ -70,5 +71,10 @@ namespace MyGame.Scripts
             // rt.sizeDelta = target.rect.size;
             rt.anchorMax = rt.anchorMin = new Vector2(0.5f, 0.5f);
         }
+
+        public void SetBGAlpha(float a)
+        {
+            backgroundImage.color = backgroundImage.color.SetA(a);
+        }
     }
 }
\ No newline at end of file