diff --git a/src/main/java/com/example/demo/entity/Book.java b/src/main/java/com/example/demo/entity/Book.java
index 06c6fe3..fab3a3b 100644
--- a/src/main/java/com/example/demo/entity/Book.java
+++ b/src/main/java/com/example/demo/entity/Book.java
@@ -9,6 +9,7 @@ import jakarta.persistence.GenerationType;
 import jakarta.persistence.Id;
 import jakarta.persistence.JoinColumn;
 import jakarta.persistence.ManyToOne;
+import jakarta.persistence.OneToOne;
 import jakarta.persistence.Table;
 
 import lombok.Data;
@@ -87,5 +88,8 @@ public class Book {
 	//申請承認フラグ
 	@Column(name = "book_approval", nullable = false)
 	private Integer bookApproval;
-
+	
+	@OneToOne(mappedBy = "book")
+	private BookLend bookLends;
+	
 }
diff --git a/src/main/java/com/example/demo/entity/BookLend.java b/src/main/java/com/example/demo/entity/BookLend.java
index c4071b8..970526f 100644
--- a/src/main/java/com/example/demo/entity/BookLend.java
+++ b/src/main/java/com/example/demo/entity/BookLend.java
@@ -7,6 +7,8 @@ import jakarta.persistence.Entity;
 import jakarta.persistence.GeneratedValue;
 import jakarta.persistence.GenerationType;
 import jakarta.persistence.Id;
+import jakarta.persistence.JoinColumn;
+import jakarta.persistence.OneToOne;
 import jakarta.persistence.Table;
 
 import lombok.Data;
@@ -22,8 +24,9 @@ public class BookLend {
 	private int lendId;
 
 	// 図書管理ID（BK-1など）
-	@Column(name = "book_manage_id", nullable = false)
-	private String bookManageId;
+	@OneToOne
+	@JoinColumn(name = "book_manage_id", referencedColumnName = "book_manage_id",nullable = false)
+	private Book book;
 
 	// 図書管理ID（BK-1など）
 	@Column(name = "employee_id", nullable = false)