diff --git a/dislocker.py b/dislocker.py
index cd2c787..1dab5b8 100644
--- a/dislocker.py
+++ b/dislocker.py
@@ -241,17 +241,19 @@ class Bot(discord.Client):
 
     def keyboard_used_check(self, **kwargs):
         try:
-            keyboard_number = int(kwargs["keyboard_number"])
-            
-            cursor = dislocker.db.cursor()
-
-            cursor.execute("SELECT * FROM keyboard_list WHERE keyboard_number=%s", (keyboard_number,))
-            keyboard_list_record = cursor.fetchall()
-            if keyboard_list_record[0][1] == None:
+            if kwargs["keyboard_number"] == None:
                 return {"result": 0, "about": "ok"}
             else:
-                return {"result": 1, "about": "keyboard_already_in_use_by_other"}
+                keyboard_number = int(kwargs["keyboard_number"])
+                
+                cursor = dislocker.db.cursor()
 
+                cursor.execute("SELECT * FROM keyboard_list WHERE keyboard_number=%s", (keyboard_number,))
+                keyboard_list_record = cursor.fetchall()
+                if keyboard_list_record[0][1] == None:
+                    return {"result": 0, "about": "ok"}
+                else:
+                    return {"result": 1, "about": "keyboard_already_in_use_by_other"}
 
         except Exception as error:
             print("キーボードの使用状況を調査中にエラーが発生しました。\nエラー内容")
@@ -265,17 +267,19 @@ class Bot(discord.Client):
     
     def mouse_used_check(self, **kwargs):
         try:
-            mouse_number = int(kwargs["mouse_number"])
-            
-            cursor = dislocker.db.cursor()
-
-            cursor.execute("SELECT * FROM mouse_list WHERE mouse_number=%s", (mouse_number,))
-            mouse_list_record = cursor.fetchall()
-            if mouse_list_record[0][1] == None:
+            if kwargs["mouse_number"] == None:
                 return {"result": 0, "about": "ok"}
             else:
-                return {"result": 1, "about": "mouse_already_in_use_by_other"}
+                mouse_number = int(kwargs["mouse_number"])
+                
+                cursor = dislocker.db.cursor()
 
+                cursor.execute("SELECT * FROM mouse_list WHERE mouse_number=%s", (mouse_number,))
+                mouse_list_record = cursor.fetchall()
+                if mouse_list_record[0][1] == None:
+                    return {"result": 0, "about": "ok"}
+                else:
+                    return {"result": 1, "about": "mouse_already_in_use_by_other"}
 
         except Exception as error:
             print("マウスの使用状況を調査中にエラーが発生しました。\nエラー内容")