diff --git a/app/controllers/nkuht_donates_controller.rb b/app/controllers/nkuht_donates_controller.rb
index a673335..ac08553 100644
--- a/app/controllers/nkuht_donates_controller.rb
+++ b/app/controllers/nkuht_donates_controller.rb
@@ -55,20 +55,20 @@ class NkuhtDonatesController < ApplicationController
 
     @nkuht_donate.donation_serial_number = NkuhtDonateMain.get_serial_number
     @nkuht_donate.donation_payment_number = NkuhtDonateMain.get_payment_number
-
-    if @nkuht_donate.donation_amount < '1'
+    
+    if @nkuht_donate.donation_amount.to_i < 1
       
         @notice = []
         @notice << t('nkuht_donate.donation_amount_err')  
         redirect_to "#{params[:referer_url]}", :notice => @notice
 
-    elsif @nkuht_donate.donation_way == '2' and @nkuht_donate.donation_amount > '30000'
+    elsif @nkuht_donate.donation_way == '2' and @nkuht_donate.donation_amount.to_i > 30000
 
         @notice = []
         @notice << t('nkuht_donate.donation_amount_atm')  
         redirect_to "#{params[:referer_url]}", :notice => @notice
 
-    elsif @nkuht_donate.donation_way == '3' and @nkuht_donate.donation_amount > '20000'
+    elsif @nkuht_donate.donation_way == '3' and @nkuht_donate.donation_amount.to_i > 20000
 
         @notice = []
         @notice << t('nkuht_donate.donation_amount_market')