The robbery was reported around 9:15 a.m. in the 3700 block of Mission Street in Bernal Heights.
The consignment store had received a call from a customer asking if the business could open early, so employees opened it two hours early to accommodate the request, according to police.
Less than five minutes after it opened, two suspects entered the store with stun guns and forced employees into a back room, police said.
The suspects, described as two men in their 40s, then ransacked the store, taking cash, a statue and collectible coins, police said.
The robbers then fled and had not been arrested as of this morning, according to police.
No one was injured in the robbery.
Anyone with information about the case is encouraged to call the Police Department's anonymous tip line at (415) 575-4444 or send a tip by text message to TIP411.