No one was reported hurt in the blaze that occurred in the shop on Link Road in Bandra (West), they said.
The fire brigade got a call at 11.15 AM, after which eight fire engines were rushed to the spot.
Efforts were still on to douse the flames, officials said.
Prima facie, the fire is suspected to have been caused due to a short-circuit in the shop which was closed when the mishap occurred, police added.