The box was found by Somchai Butrsakhon, 55, in front of an ATM machine at the mouth of Soi Pracharaj Bampen 6.
Somchai contacted the JS100 traffic radio station that informed the Huay Kwang police station.
A Kasikorn Bank official rushed to check the box at the station and confirmed it belonged to his bank and that it contained Bt1,000 banknotes worth Bt1.5 million.