diff --git a/src/handler/test_handler.rs b/src/handler/test_handler.rs
index 795b5fe..37ffd62 100644
--- a/src/handler/test_handler.rs
+++ b/src/handler/test_handler.rs
@@ -1,26 +1,38 @@
-use crate::models;
+use crate::models::test::TestObj;
 use crate::usecase;
-use async_graphql::Object;
+use async_graphql::{Error, InputObject, MergedObject, Object, SimpleObject};
 
 #[derive(Default)]
 pub struct TestQuery;
 
 #[Object]
 impl TestQuery {
-    async fn get_obj(&self) -> models::test::TestObj {
+    async fn obj(&self) -> TestObj {
         usecase::test::get_obj()
     }
 }
 
+#[derive(Default, MergedObject)]
+pub struct TestMutation(CreateTestObjMutation);
+
 #[derive(Default)]
-pub struct TestMutation;
+pub struct CreateTestObjMutation;
+
+#[derive(InputObject)]
+pub struct CreateTestObjInput {
+    pub name: String,
+    pub num: usize,
+}
+
+#[derive(SimpleObject, Debug)]
+pub struct CreateTestObjPayload {
+    pub obj: TestObj,
+}
 
 #[Object]
-impl TestMutation {
-    async fn create_obj(
-        &self,
-        input_obj: models::test::CreateTestObjInput,
-    ) -> Result<models::test::TestObj, std::io::Error> {
-        usecase::test::create_obj(input_obj)
+impl CreateTestObjMutation {
+    async fn create_obj(&self, input: CreateTestObjInput) -> Result<CreateTestObjPayload, Error> {
+        let obj = usecase::test::create_obj(input.name, input.num)?;
+        Ok(CreateTestObjPayload { obj })
     }
 }
diff --git a/src/models/test.rs b/src/models/test.rs
index 9ef2b9e..d67e857 100644
--- a/src/models/test.rs
+++ b/src/models/test.rs
@@ -1,4 +1,4 @@
-use async_graphql::{InputObject, SimpleObject};
+use async_graphql::SimpleObject;
 
 #[derive(SimpleObject, Debug)]
 pub struct TestObj {
@@ -6,9 +6,3 @@ pub struct TestObj {
     pub name: String,
     pub num: usize,
 }
-
-#[derive(InputObject)]
-pub struct CreateTestObjInput {
-    pub name: String,
-    pub num: usize,
-}
diff --git a/src/usecase/test.rs b/src/usecase/test.rs
index b32d69c..7597020 100644
--- a/src/usecase/test.rs
+++ b/src/usecase/test.rs
@@ -1,17 +1,15 @@
-use crate::models;
+use crate::models::test::TestObj;
 
-pub fn get_obj() -> models::test::TestObj {
-    models::test::TestObj {
+pub fn get_obj() -> TestObj {
+    TestObj {
         id: "test".to_string(),
         name: "test_name".to_string(),
         num: 1,
     }
 }
 
-pub fn create_obj(
-    models::test::CreateTestObjInput { name, num }: models::test::CreateTestObjInput,
-) -> Result<models::test::TestObj, std::io::Error> {
-    let input = models::test::TestObj {
+pub fn create_obj(name: String, num: usize) -> Result<TestObj, std::io::Error> {
+    let input = TestObj {
         id: "test_input".to_string(),
         name,
         num,