diff --git a/ecs/jskult-webapp/src/model/view/ultmarc_doctor_info_view_model.py b/ecs/jskult-webapp/src/model/view/ultmarc_doctor_info_view_model.py
index d74ee6fe..4ed0537a 100644
--- a/ecs/jskult-webapp/src/model/view/ultmarc_doctor_info_view_model.py
+++ b/ecs/jskult-webapp/src/model/view/ultmarc_doctor_info_view_model.py
@@ -45,17 +45,18 @@ class UltmarcDoctorInfoViewModel(BaseModel):
     def is_input_birthday_format(self):
         if self.doctor_info_data.birthday is None or len(self.doctor_info_data.birthday) == 0:
             return ''
-        if len(self.doctor_info_data.birthday.replace(" ", "")) == 8:
+        birthday = self.doctor_info_data.birthday.replace(" ", "")
+        if len(birthday) == 8:
             # ８桁の場合、yyyy/mm/ddとする
-            return self._format_date_string(self.doctor_info_data.birthday)
-        if len(self.doctor_info_data.birthday.replace(" ", "")) == 4:
-            birthday = self.doctor_info_data.birthday.replace(" ", "")
+            return f'{birthday[0:4]}/{birthday[4:6]}/{birthday[6:8]}'
+        if len(birthday) == 4:
             # ４桁の場合、mm/ddとする
-            return '/'.join([birthday[0:2], birthday[2:4]])
+            return f'{birthday[0:2]}/{birthday[2:4]}'
         # 規格外の場合は、空表示とする
         return ''
 
     # 利用停止区分
+
     def is_input_use_stop_div_category_name(self):
         if not self.doctor_info_data.use_stop_div:
             return ''