diff --git a/backend/src/main/java/com/example/todoapp/controller/ToBuysController.java b/backend/src/main/java/com/example/todoapp/controller/ToBuysController.java
new file mode 100644
index 0000000..fbb0603
--- /dev/null
+++ b/backend/src/main/java/com/example/todoapp/controller/ToBuysController.java
@@ -0,0 +1,22 @@
+package com.example.todoapp.controller;
+
+import com.example.todoapp.dto.ToBuyDTO;
+import com.example.todoapp.service.ToBuysService;
+import jakarta.validation.Valid;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.*;
+
+@RestController
+@RequestMapping("/api/tobuy/add")
+public class ToBuysController {
+
+    @Autowired
+    private ToBuysService toBuysService;
+
+    @PostMapping
+    public ResponseEntity<String> addToBuys(@Valid @RequestBody ToBuyDTO dto) {
+        toBuysService.addToBuys(dto);
+        return ResponseEntity.ok("Item added to 'To Buys' successfully");
+    }
+}
\ No newline at end of file
diff --git a/backend/src/main/java/com/example/todoapp/dto/ToBuyDTO.java b/backend/src/main/java/com/example/todoapp/dto/ToBuyDTO.java
new file mode 100644
index 0000000..36295bf
--- /dev/null
+++ b/backend/src/main/java/com/example/todoapp/dto/ToBuyDTO.java
@@ -0,0 +1,18 @@
+package com.example.todoapp.dto;
+
+import lombok.Data;
+/**
+ * カテゴリDTOクラス
+ * このクラスはタスクのカテゴリ情報を表します。
+ * カテゴリは名前、色、所有ユーザーなどの情報を持ちます。
+ * 
+ */
+
+ @Data
+ public class ToBuyDTO {
+    private Long  stuffsId;
+    private Long userId;
+
+    private int amount;
+    private String store;
+ }
\ No newline at end of file
diff --git a/backend/src/main/java/com/example/todoapp/repository/StuffsRepository.java b/backend/src/main/java/com/example/todoapp/repository/StuffsRepository.java
new file mode 100644
index 0000000..3c29f31
--- /dev/null
+++ b/backend/src/main/java/com/example/todoapp/repository/StuffsRepository.java
@@ -0,0 +1,12 @@
+package com.example.todoapp.repository;
+
+import com.example.todoapp.model.Stuffs;
+import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.stereotype.Repository;
+
+import java.util.Optional;
+
+@Repository
+public interface StuffsRepository extends JpaRepository<Stuffs, Long> {
+    Optional<Stuffs> findById(Long id);
+}
\ No newline at end of file
diff --git a/backend/src/main/java/com/example/todoapp/repository/ToBuysRepository.java b/backend/src/main/java/com/example/todoapp/repository/ToBuysRepository.java
new file mode 100644
index 0000000..ff6469f
--- /dev/null
+++ b/backend/src/main/java/com/example/todoapp/repository/ToBuysRepository.java
@@ -0,0 +1,9 @@
+package com.example.todoapp.repository;
+
+import com.example.todoapp.model.ToBuys;
+import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.stereotype.Repository;
+
+@Repository
+public interface ToBuysRepository extends JpaRepository<ToBuys, Integer> {
+}
\ No newline at end of file
diff --git a/backend/src/main/java/com/example/todoapp/service/ToBuysService.java b/backend/src/main/java/com/example/todoapp/service/ToBuysService.java
new file mode 100644
index 0000000..2a44acb
--- /dev/null
+++ b/backend/src/main/java/com/example/todoapp/service/ToBuysService.java
@@ -0,0 +1,51 @@
+package com.example.todoapp.service;
+
+import com.example.todoapp.dto.ToBuyDTO;
+import com.example.todoapp.model.Stuffs;
+import com.example.todoapp.model.ToBuys;
+import com.example.todoapp.model.User;
+import com.example.todoapp.repository.StuffsRepository;
+import com.example.todoapp.repository.ToBuysRepository;
+import com.example.todoapp.repository.UserRepository;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.stereotype.Service;
+
+import java.util.Optional;
+
+@Service
+public class ToBuysService {
+
+    @Autowired
+    private ToBuysRepository toBuysRepository;
+
+    @Autowired
+    private UserRepository userRepository;
+
+    @Autowired
+    private StuffsRepository stuffsRepository;
+
+    public void addToBuys(ToBuyDTO toBuyDTO) {
+
+        //get user
+        Optional<User> user = userRepository.findById(toBuyDTO.getUserId());
+        if (!user.isPresent()) { 
+            throw new RuntimeException("no: " + toBuyDTO.getUserId());  
+        }
+
+        //get stuffs
+        Optional<Stuffs> stuffs = stuffsRepository.findById(toBuyDTO.getStuffsId());
+        if (!stuffs.isPresent()) {
+            throw new RuntimeException("材料不存在");
+        }
+
+        ToBuys toBuys = new ToBuys();
+        toBuys.setUser_id(user.get());
+        toBuys.setStuffs(stuffs.get());
+        toBuys.setAmount(toBuyDTO.getAmount());
+        toBuys.setStore(toBuyDTO.getStore());
+
+        // 保存到数据库
+        toBuysRepository.save(toBuys);
+
+    }
+}
\ No newline at end of file