diff --git a/lib/use_case/relationship/create.rb b/lib/use_case/relationship/create.rb
index 61d7cbcf..54f61f39 100644
--- a/lib/use_case/relationship/create.rb
+++ b/lib/use_case/relationship/create.rb
@@ -37,15 +37,15 @@ module UseCase
 
       def find_source_user
         user_id = @current_user_id
-        User.find(user_id)
+        ::User.find(user_id)
       rescue ActiveRecord::RecordNotFound
         raise Errors::UserNotFound
       end
 
       def find_target_user
         target_user = @target_user
-        return target_user if target_user.is_a?(User)
-        User.find_by!(screen_name: target_user)
+        return target_user if target_user.is_a?(::User)
+        ::User.find_by!(screen_name: target_user)
       rescue ActiveRecord::RecordNotFound
         raise Errors::UserNotFound
       end
diff --git a/lib/use_case/relationship/destroy.rb b/lib/use_case/relationship/destroy.rb
index 0b0fcf54..3788f38c 100644
--- a/lib/use_case/relationship/destroy.rb
+++ b/lib/use_case/relationship/destroy.rb
@@ -37,15 +37,15 @@ module UseCase
 
       def find_source_user
         user_id = @current_user_id
-        User.find(user_id)
+        ::User.find(user_id)
       rescue ActiveRecord::RecordNotFound
         raise Errors::UserNotFound
       end
 
       def find_target_user
         target_user = @target_user
-        return target_user if target_user.is_a?(User)
-        User.find_by!(screen_name: target_user)
+        return target_user if target_user.is_a?(::User)
+        ::User.find_by!(screen_name: target_user)
       rescue ActiveRecord::RecordNotFound
         raise Errors::UserNotFound
       end