The explosion took place at about 5.30am at the shop on Santirat Road and fire-fighters in 10 trucks spent over an hour putting out the blaze.
Yaha police investigator Lt-Colonel Prasom Luangpul said the shop was among the district’s large grocery suppliers.
He said two explosions occurred at the side of the building before the fire ravaged it.
Police suspect that someone placed a home-made bomb near the shop and detonated it.