The van had halted near a petrol pump and a cashier of the company had gone to the petrol pump's office for cash collection when the incident took place.
As the driver got out to get air filled in tyres, two men on motorbike came and fled with a bag containing Rs 22.5 lakh kept in the van.
The van collected cash from five petrol pumps daily and deposited it in banks.
The accused will be identified and nabbed soon, said police commissioner Manoj Shashidhar.