Police say the robber entered the shop on the Oldpark Road just after 6.30 pm and threatened two female members of staff.
As he fled towards the Westland area with a handful of cash, the man momentarily stopped by members of the public.
A waiting motorcycle rider then sped off towards Alliance Road.
Neither member of staff was injured during the attack.
During the robbery, damage was caused to the premises, say police.
Detectives at Antrim Road CID have appealed for information about the robbers to contact them on 0845 600 8000.