Fire Department officials said while furniture, computers, printers, electronic items and some record were gutted, the blaze did not spread in ATM and locker chambers of the bank.
Two fire tenders were pressed into service to douse the flames that lasted for three hours, they said.
The incident could have occurred due to an electric short circuit, the officials said.
According to a bank official, a bank employee turned on the main power switch of the bank premises in the morning after which the fire started. She, however, managed to escape.
ACP Ambala, Hitesh Yadav said police are probing the incident.