Staff told police a masked man entered the business on Main Street late Thursday evening armed with a firearm.
He pointed the gun at an employee and demanded money and cigarettes.
He then took off in an older four-door, light-coloured sedan with cash and smokes.
No injuries were reported during the armed robbery.
Police have released surveillance photos of the suspect and the vehicle.
Anyone who is able to identify the man or vehicle, or has further information, is asked to contact Shellbrook RCMP at 306-747-2606 or Crime Stoppers at 1-800-222-8477.