diff --git a/rest-controller-practice/src/main/java/com/example/restcontroller/user/controller/ApiUserInterestController.java b/rest-controller-practice/src/main/java/com/example/restcontroller/user/controller/ApiUserInterestController.java
new file mode 100644
index 00000000..019e47c0
--- /dev/null
+++ b/rest-controller-practice/src/main/java/com/example/restcontroller/user/controller/ApiUserInterestController.java
@@ -0,0 +1,33 @@
+package com.example.restcontroller.user.controller;
+
+import com.auth0.jwt.exceptions.JWTVerificationException;
+import com.example.restcontroller.board.model.ServiceResult;
+import com.example.restcontroller.common.model.ResponseResult;
+import com.example.restcontroller.user.service.UserService;
+import com.example.restcontroller.util.JWTUtils;
+import lombok.RequiredArgsConstructor;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.PathVariable;
+import org.springframework.web.bind.annotation.PutMapping;
+import org.springframework.web.bind.annotation.RequestHeader;
+import org.springframework.web.bind.annotation.RestController;
+
+@RestController
+@RequiredArgsConstructor
+public class ApiUserInterestController {
+
+    private final UserService userService;
+
+    @PutMapping("/api/user/{id}/interest")
+    public ResponseEntity<?> chapter3_18(@PathVariable Long id,
+                                         @RequestHeader("TOKEN") String token) {
+        String email = "";
+        try {
+            email = JWTUtils.getIssuer(token);
+        } catch (JWTVerificationException e) {
+            return ResponseResult.fail("토큰 정보가 정확하지 않습니다.");
+        }
+        ServiceResult result = userService.addInterestUser(id, email);
+        return ResponseResult.result(result);
+    }
+}
diff --git a/rest-controller-practice/src/main/java/com/example/restcontroller/user/entity/User.java b/rest-controller-practice/src/main/java/com/example/restcontroller/user/entity/User.java
index a10eaa39..c8e0f656 100644
--- a/rest-controller-practice/src/main/java/com/example/restcontroller/user/entity/User.java
+++ b/rest-controller-practice/src/main/java/com/example/restcontroller/user/entity/User.java
@@ -72,6 +72,14 @@ public class User {
     @OneToMany(mappedBy = "user")
     List<BoardBookmark> boardBookmarkList = new ArrayList<>();
 
+    @JsonIgnore
+    @OneToMany(mappedBy = "user")
+    List<UserInterest> userList = new ArrayList<>();
+
+    @JsonIgnore
+    @OneToMany(mappedBy = "interestUser")
+    List<UserInterest> userInterestList = new ArrayList<>();
+
     @PrePersist
     public void prePersist() {
         status = status == null ? UserStatus.USING : status;
diff --git a/rest-controller-practice/src/main/java/com/example/restcontroller/user/entity/UserInterest.java b/rest-controller-practice/src/main/java/com/example/restcontroller/user/entity/UserInterest.java
new file mode 100644
index 00000000..6af9633b
--- /dev/null
+++ b/rest-controller-practice/src/main/java/com/example/restcontroller/user/entity/UserInterest.java
@@ -0,0 +1,29 @@
+package com.example.restcontroller.user.entity;
+
+import lombok.*;
+
+import javax.persistence.*;
+import java.time.LocalDateTime;
+
+
+@Getter @Setter
+@AllArgsConstructor
+@NoArgsConstructor
+@Builder
+@Entity
+public class UserInterest {
+
+    @Id @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private Long id;
+
+    @ManyToOne
+    @JoinColumn(foreignKey = @ForeignKey(name = "FK_USER_INTEREST_USER_ID"))
+    private User user;
+
+    @ManyToOne
+    @JoinColumn(foreignKey = @ForeignKey(name = "FK_USER_INTEREST_INTEREST_USER_ID"))
+    private User interestUser;
+
+    private LocalDateTime regDate;
+
+}
diff --git a/rest-controller-practice/src/main/java/com/example/restcontroller/user/repository/UserInterestRepository.java b/rest-controller-practice/src/main/java/com/example/restcontroller/user/repository/UserInterestRepository.java
new file mode 100644
index 00000000..d7fcccdb
--- /dev/null
+++ b/rest-controller-practice/src/main/java/com/example/restcontroller/user/repository/UserInterestRepository.java
@@ -0,0 +1,12 @@
+package com.example.restcontroller.user.repository;
+
+import com.example.restcontroller.user.entity.User;
+import com.example.restcontroller.user.entity.UserInterest;
+import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.stereotype.Repository;
+
+@Repository
+public interface UserInterestRepository extends JpaRepository<UserInterest, Long> {
+
+    Long countByUserAndInterestUser(User user, User interestUser);
+}
diff --git a/rest-controller-practice/src/main/java/com/example/restcontroller/user/service/UserService.java b/rest-controller-practice/src/main/java/com/example/restcontroller/user/service/UserService.java
index b719d5bc..cb32f8be 100644
--- a/rest-controller-practice/src/main/java/com/example/restcontroller/user/service/UserService.java
+++ b/rest-controller-practice/src/main/java/com/example/restcontroller/user/service/UserService.java
@@ -1,5 +1,6 @@
 package com.example.restcontroller.user.service;
 
+import com.example.restcontroller.board.model.ServiceResult;
 import com.example.restcontroller.user.model.UserNoticeCount;
 import com.example.restcontroller.user.model.UserLogCount;
 import com.example.restcontroller.user.model.UserResponse;
@@ -18,4 +19,6 @@ public interface UserService {
     List<UserLogCount> getUserLogCount();
 
     List<UserLogCount> getUserLikeBest();
+
+    ServiceResult addInterestUser(Long id, String email);
 }
diff --git a/rest-controller-practice/src/main/java/com/example/restcontroller/user/service/UserServiceImpl.java b/rest-controller-practice/src/main/java/com/example/restcontroller/user/service/UserServiceImpl.java
index c9d56320..513a4d4d 100644
--- a/rest-controller-practice/src/main/java/com/example/restcontroller/user/service/UserServiceImpl.java
+++ b/rest-controller-practice/src/main/java/com/example/restcontroller/user/service/UserServiceImpl.java
@@ -1,12 +1,16 @@
 package com.example.restcontroller.user.service;
 
 
+import com.example.restcontroller.board.model.ServiceResult;
+import com.example.restcontroller.user.entity.User;
+import com.example.restcontroller.user.entity.UserInterest;
 import com.example.restcontroller.user.entity.UserStatus;
 import com.example.restcontroller.user.model.UserNoticeCount;
 import com.example.restcontroller.user.model.UserLogCount;
 import com.example.restcontroller.user.model.UserResponse;
 import com.example.restcontroller.user.model.UserSummary;
 import com.example.restcontroller.user.repository.UserCustomRepository;
+import com.example.restcontroller.user.repository.UserInterestRepository;
 import com.example.restcontroller.user.repository.UserRepository;
 import lombok.RequiredArgsConstructor;
 import org.springframework.stereotype.Service;
@@ -16,6 +20,7 @@ import java.time.LocalDate;
 import java.time.LocalDateTime;
 import java.time.LocalTime;
 import java.util.List;
+import java.util.Optional;
 import java.util.stream.Collectors;
 
 @Service
@@ -25,6 +30,7 @@ public class UserServiceImpl implements UserService {
 
     private final UserRepository userRepository;
     private final UserCustomRepository userCustomRepository;
+    private final UserInterestRepository userInterestRepository;
 
     @Override
     public UserSummary getUserStatusCount() {
@@ -62,4 +68,37 @@ public class UserServiceImpl implements UserService {
     public List<UserLogCount> getUserLikeBest() {
         return userCustomRepository.findUserLikeBest();
     }
+
+    @Transactional
+    @Override
+    public ServiceResult addInterestUser(Long id, String email) {
+        Optional<User> optionalUser = userRepository.findByEmail(email);
+        if (!optionalUser.isPresent()) {
+            return ServiceResult.fail("회원 정보가 없습니다.");
+        }
+        User userEntity = optionalUser.get();
+
+        Optional<User> optionalInterestUser = userRepository.findById(id);
+        if (!optionalInterestUser.isPresent()) {
+            return ServiceResult.fail("관심 사용자에 추가할 회원 정보가 없습니다.");
+        }
+        User interestUserEntity = optionalInterestUser.get();
+
+        if (userEntity.getId() == interestUserEntity.getId()) {
+            return ServiceResult.fail("자기 자신은 추가할 수 없습니다.");
+        }
+
+        if (userInterestRepository.countByUserAndInterestUser(userEntity, interestUserEntity) > 0) {
+            return ServiceResult.fail("이미 관심사용자 목록에 추가된 사용자 입니다.");
+        }
+
+        UserInterest userInterest = UserInterest.builder()
+                .user(userEntity)
+                .interestUser(interestUserEntity)
+                .regDate(LocalDateTime.now())
+                .build();
+        userInterestRepository.save(userInterest);
+
+        return ServiceResult.success();
+    }
 }
diff --git a/rest-controller-practice/src/main/java/com/example/restcontroller/util/JWTUtils.java b/rest-controller-practice/src/main/java/com/example/restcontroller/util/JWTUtils.java
index d992ba56..df8f1554 100644
--- a/rest-controller-practice/src/main/java/com/example/restcontroller/util/JWTUtils.java
+++ b/rest-controller-practice/src/main/java/com/example/restcontroller/util/JWTUtils.java
@@ -2,7 +2,9 @@ package com.example.restcontroller.util;
 
 import com.auth0.jwt.JWT;
 import com.auth0.jwt.algorithms.Algorithm;
+import com.auth0.jwt.exceptions.JWTVerificationException;
 import com.auth0.jwt.exceptions.SignatureVerificationException;
+import com.example.restcontroller.common.model.ResponseResult;
 import com.example.restcontroller.user.exception.PasswordNotMatchException;
 import lombok.experimental.UtilityClass;
 import org.springframework.security.crypto.bcrypt.BCrypt;