diff --git a/adminfront/src/features/users/UserCreatePage.tsx b/adminfront/src/features/users/UserCreatePage.tsx
index c6b83fb3..01622ab3 100644
--- a/adminfront/src/features/users/UserCreatePage.tsx
+++ b/adminfront/src/features/users/UserCreatePage.tsx
@@ -290,9 +290,15 @@ function UserCreatePage() {
     patch: Partial<UserAppointment>,
   ) => {
     setAdditionalAppointments((current) =>
-      current.map((appointment, currentIndex) =>
-        currentIndex === index ? { ...appointment, ...patch } : appointment,
-      ),
+      current.map((appointment, currentIndex) => {
+        if (currentIndex === index) {
+          return { ...appointment, ...patch };
+        }
+        if (patch.isOwner === true) {
+          return { ...appointment, isOwner: false };
+        }
+        return appointment;
+      }),
     );
   };
 
diff --git a/adminfront/src/features/users/UserDetailPage.tsx b/adminfront/src/features/users/UserDetailPage.tsx
index 501c3017..f115e165 100644
--- a/adminfront/src/features/users/UserDetailPage.tsx
+++ b/adminfront/src/features/users/UserDetailPage.tsx
@@ -536,9 +536,15 @@ function UserDetailPage() {
     patch: Partial<UserAppointment>,
   ) => {
     setAdditionalAppointments((current) =>
-      current.map((appointment, currentIndex) =>
-        currentIndex === index ? { ...appointment, ...patch } : appointment,
-      ),
+      current.map((appointment, currentIndex) => {
+        if (currentIndex === index) {
+          return { ...appointment, ...patch };
+        }
+        if (patch.isOwner === true) {
+          return { ...appointment, isOwner: false };
+        }
+        return appointment;
+      }),
     );
   };
 
@@ -1168,6 +1174,7 @@ function UserDetailPage() {
                                         isOwner: checked === true,
                                       })
                                     }
+                                    disabled={appointment.isPrimary}
                                     aria-label={t(
                                       "ui.admin.users.detail.form.appointment_owner",
                                       "대표 조직",