The Belmont Road shop was robbed shortly after 4 pm on Monday afternoon.
A robber targeted the premises on Sunday morning.
The robber in both incidents was described as being in his 20s and about 5ft 10ins tall.
Police say there are investigating whether the robberies are linked.
Anyone with information about the robber is asked to contact detectives in the Reactive and Organised Crime Branch at Musgrave PSNI on the 101 number.