Police said the man entered the Good Luck Sweepstakes on Capital Boulevard just after midnight and was armed with a handgun.
The suspect demanded cash from an employee and fled the scene on foot.
The man is described as a heavyset, bearded black male with a dark complexion who stands about 6 feet tall. At the time of the robbery, he was wearing a red and black checkered button-up shirt, khakis, and a baseball hat.
Anyone who recognizes the suspect is asked to call Raleigh CrimeStoppers at (919) 834-HELP.