diff --git a/src/main/java/com/codingwasabi/howtodo/web/account/AccountController.java b/src/main/java/com/codingwasabi/howtodo/web/account/AccountController.java
index 2177c72..68612d6 100644
--- a/src/main/java/com/codingwasabi/howtodo/web/account/AccountController.java
+++ b/src/main/java/com/codingwasabi/howtodo/web/account/AccountController.java
@@ -3,6 +3,7 @@
 import static org.springframework.http.HttpStatus.*;
 
 import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.DeleteMapping;
 import org.springframework.web.bind.annotation.GetMapping;
 import org.springframework.web.bind.annotation.RequestParam;
 import org.springframework.web.bind.annotation.RestController;
@@ -33,4 +34,10 @@ ResponseEntity<Void> getValidationNickname(@RequestParam("value") String nicknam
 	ResponseEntity<String> get(@LoginAccount Account account) {
 		return ResponseEntity.ok(account.getEmail() + " : " + account.getProvider());
 	}
+
+	@DeleteMapping("/me")
+	ResponseEntity<Void> reset(@LoginAccount Account account) {
+		accountService.reset(account);
+		return ResponseEntity.noContent().build();
+	}
 }
diff --git a/src/main/java/com/codingwasabi/howtodo/web/account/AccountService.java b/src/main/java/com/codingwasabi/howtodo/web/account/AccountService.java
index 0a1c1c8..9781876 100644
--- a/src/main/java/com/codingwasabi/howtodo/web/account/AccountService.java
+++ b/src/main/java/com/codingwasabi/howtodo/web/account/AccountService.java
@@ -6,4 +6,6 @@ public interface AccountService {
 	Account findAccount(Long userId);
 
 	boolean isValidNickname(String nickname);
+
+	void reset(Account account);
 }
diff --git a/src/main/java/com/codingwasabi/howtodo/web/account/AccountServiceImpl.java b/src/main/java/com/codingwasabi/howtodo/web/account/AccountServiceImpl.java
index d230f8e..3227920 100644
--- a/src/main/java/com/codingwasabi/howtodo/web/account/AccountServiceImpl.java
+++ b/src/main/java/com/codingwasabi/howtodo/web/account/AccountServiceImpl.java
@@ -4,6 +4,9 @@
 import org.springframework.transaction.annotation.Transactional;
 
 import com.codingwasabi.howtodo.web.account.entity.Account;
+import com.codingwasabi.howtodo.web.calendar.CalendarRepository;
+import com.codingwasabi.howtodo.web.dailyplan.DailyPlanRepository;
+import com.codingwasabi.howtodo.web.dailyplan.entity.DailyPlan;
 
 import lombok.RequiredArgsConstructor;
 
@@ -12,6 +15,7 @@
 @RequiredArgsConstructor
 public class AccountServiceImpl implements AccountService {
 	private final AccountRepository accountRepository;
+	private final CalendarRepository calendarRepository;
 
 	@Override
 	public Account findAccount(Long accountId) {
@@ -24,4 +28,9 @@ public Account findAccount(Long accountId) {
 	public boolean isValidNickname(String nickname) {
 		return !accountRepository.existsByNickname(nickname);
 	}
+
+	@Override
+	public void reset(Account account) {
+		calendarRepository.deleteByAccount(account);
+	}
 }
diff --git a/src/main/java/com/codingwasabi/howtodo/web/calendar/CalendarRepository.java b/src/main/java/com/codingwasabi/howtodo/web/calendar/CalendarRepository.java
index 1cb14fa..2703e82 100644
--- a/src/main/java/com/codingwasabi/howtodo/web/calendar/CalendarRepository.java
+++ b/src/main/java/com/codingwasabi/howtodo/web/calendar/CalendarRepository.java
@@ -12,4 +12,6 @@
 
 public interface CalendarRepository extends JpaRepository<Calendar, Long> {
 	Optional<Calendar> findByAccount(Account account);
+
+	void deleteByAccount(Account account);
 }
diff --git a/src/main/java/com/codingwasabi/howtodo/web/dailyplan/entity/DailyPlan.java b/src/main/java/com/codingwasabi/howtodo/web/dailyplan/entity/DailyPlan.java
index 77e4030..7241e6f 100644
--- a/src/main/java/com/codingwasabi/howtodo/web/dailyplan/entity/DailyPlan.java
+++ b/src/main/java/com/codingwasabi/howtodo/web/dailyplan/entity/DailyPlan.java
@@ -38,10 +38,10 @@ public class DailyPlan {
 	@ManyToOne(fetch = FetchType.LAZY)
 	private Account account;
 
-	@OneToMany(mappedBy = "dailyPlan", cascade = CascadeType.ALL)
+	@OneToMany(mappedBy = "dailyPlan", cascade = CascadeType.ALL, orphanRemoval = true)
 	private List<ToDo> toDos = new ArrayList<>();
 
-	@OneToMany(mappedBy = "dailyPlan", cascade = CascadeType.ALL)
+	@OneToMany(mappedBy = "dailyPlan", cascade = CascadeType.ALL, orphanRemoval = true)
 	private List<Comment> comments = new ArrayList<>();
 
 	@Setter
diff --git a/src/main/java/com/codingwasabi/howtodo/web/todo/entity/ToDo.java b/src/main/java/com/codingwasabi/howtodo/web/todo/entity/ToDo.java
index 119d6ae..96a0bcc 100644
--- a/src/main/java/com/codingwasabi/howtodo/web/todo/entity/ToDo.java
+++ b/src/main/java/com/codingwasabi/howtodo/web/todo/entity/ToDo.java
@@ -2,6 +2,7 @@
 
 import java.time.LocalDate;
 
+import javax.persistence.CascadeType;
 import javax.persistence.Entity;
 import javax.persistence.FetchType;
 import javax.persistence.GeneratedValue;
@@ -28,7 +29,7 @@ public class ToDo {
 
 	private double hour;
 
-	@OneToOne(fetch = FetchType.LAZY)
+	@OneToOne(fetch = FetchType.LAZY, orphanRemoval = true, cascade = CascadeType.REMOVE)
 	private Exam exam;
 
 	@Setter