Five of them are in critical condition, doctors say.
The incident occurred at the food shop 'Mithai Swad' at Lalbagh intersection Saturday afternoon, Dhaka Metropolitan Police Deputy Commissioner Md Ibrahim Khan said.
The victims are employees of the shop Maruf Hossain, 20, and 'Sabuj', 20, passersby Sabbir, 22, Maqbul Hossain, 35, Farzana Panna, 28, Sonam Uddin, 50, and Hazrat Ali, 45, and rickshaw-puller 'Abdullah', 30.
DMCH Burns Unit surgeon Partha Shankar Paul told bdnews24.com that five of them were in critical condition.
DMP DC Ibrahim said the walls, doors, windows, and furniture of the shop were shattered in the explosion.
He said police initially suspected a gas cylinder exploded at the shop, causing the casualties.
But, Fire Service Senior Station Officer Mofazzal Karim told bdnew24.com after visiting the spot said that the compressor of the fridge at the eatery might be the cause of the blast.
He said the Fire Service was investigating the incident. "Police bomb disposal unit has also collected evidence," he added.