diff --git a/core/api_coupon.go b/core/api_coupon.go
index 18bda65..f475a02 100644
--- a/core/api_coupon.go
+++ b/core/api_coupon.go
@@ -261,8 +261,8 @@ func listAllCouponNames(mongoClient gocommon.MongoClient, w http.ResponseWriter,
 }
 
 func useCoupon(mongoClient gocommon.MongoClient, w http.ResponseWriter, r *http.Request) {
-	acc, ok := gocommon.ReadObjectIDFormValue(r.Form, "accid")
-	if !ok || acc.IsZero() {
+	acc, _ := gocommon.ReadStringFormValue(r.Form, "accid")
+	if len(acc) == 0 {
 		w.WriteHeader(http.StatusBadRequest)
 		return
 	}
@@ -285,7 +285,7 @@ func useCoupon(mongoClient gocommon.MongoClient, w http.ResponseWriter, r *http.
 		// 무한 쿠폰일 수 있으므로 존재하는지 확인
 		if err := mongoClient.FindOneAs(CollectionCoupon, bson.M{
 			"_id": roundObj,
-		}, &coupon, options.FindOne().SetProjection(bson.M{"_id": 0, "effect": 1, "name": 1, "reason": 1, "total": 1, "expire": 1})); err != nil {
+		}, &coupon, options.FindOne().SetProjection(bson.M{"_id": 0, "effect": 1, "name": 1, "total": 1, "expire": 1})); err != nil {
 			logger.Println(err)
 			w.WriteHeader(http.StatusInternalServerError)
 			return