diff --git a/HSUCO_Cargo_Garage_Operation_Program/Database.cs b/HSUCO_Cargo_Garage_Operation_Program/Database.cs
index 09b80b8..7e154c0 100644
--- a/HSUCO_Cargo_Garage_Operation_Program/Database.cs
+++ b/HSUCO_Cargo_Garage_Operation_Program/Database.cs
@@ -184,14 +184,16 @@ namespace HSUCO_Cargo_Garage_Operation_Program
         /// </summary>
         /// <param name="CargoVehicleNumber">화물차 번호</param>
         /// <returns>중복 여부</returns>
-        public static bool ApplicantCheckAlready(string CargoVehicleNumber)
+        public static bool ApplicantCheckAlready(string cargoVehicleNumber)
         {
             var count = 0;
-            var query = $"SELECT COUNT(*) FROM ViewApplicantList WHERE CargoVehicleNumber = '{CargoVehicleNumber}' AND RegistrationStatus={(int)ERegistrationStatus.Wait};";
+            var query = $"SELECT COUNT(*) FROM ViewApplicantList WHERE CargoVehicleNumber = '@cargoVehicleNumbe' AND RegistrationStatus=@registrationStatus;";
 
             using (var command = _sqLiteConnection.CreateCommand())
             {
                 command.CommandText = query;
+                command.Parameters.AddWithValue("@cargoVehicleNumber", cargoVehicleNumber);
+                command.Parameters.AddWithValue("@registrationStatus", (int)ERegistrationStatus.Wait);
 
                 using (var reader = command.ExecuteReader())
                 {