diff --git a/src/main/java/site/model/Registrant.java b/src/main/java/site/model/Registrant.java
index 2d3ba24..358a509 100644
--- a/src/main/java/site/model/Registrant.java
+++ b/src/main/java/site/model/Registrant.java
@@ -86,15 +86,15 @@ public static class NumberGenerator {
 
         @Id
         @GeneratedValue
-        private int id;
+        private Integer id;
 
         private long counter;
 
-        public int getId() {
+        public Integer getId() {
             return id;
         }
 
-        public void setId(int id) {
+        public void setId(Integer id) {
             this.id = id;
         }
 
diff --git a/src/main/java/site/repository/RegistrantNumberGeneratorRepository.java b/src/main/java/site/repository/RegistrantNumberGeneratorRepository.java
index 726436f..89c7dc4 100644
--- a/src/main/java/site/repository/RegistrantNumberGeneratorRepository.java
+++ b/src/main/java/site/repository/RegistrantNumberGeneratorRepository.java
@@ -7,7 +7,7 @@
 
 @NoRepositoryBean
 public interface RegistrantNumberGeneratorRepository<T extends Registrant.NumberGenerator> extends
-    JpaRepository<T, Long> {
+    JpaRepository<T, Integer> {
     T findFirstByOrderByIdAsc();
 
     default Class<?> repositoryClass() {