Six armed robbers entered the chit fund office at B T Sarkar Road at about 3 pm, forced the staff to open the vault and looted Rs four lakh from there.
They also looted Rs 50,000 from the counter and mobile phone of staff members and customers, the sources said.
They then fled in three motorbikes towards Jharkhand.
The robbers, who were speaking in Bengali and Hindi, had snatched the rifle of the security guard at gunpoint, the sources said.
