A man with a handgun entered the station and walked toward the counter, police said.
He went behind the counter, put his gun to the head of the store clerk and demanded money from the register, police said. The suspect took cash and fled on foot, headed south on Lisa Lane.
The suspect is described as a black man about 23-25 years old, 6 feet tall and weighing about 200 pounds, police said. He was last seen wearing a black motorcycle helmet with a clear visor and black jacket, and was armed with a black semi-automatic handgun.
Anyone with information about the robbery is asked to contact the Pleasant Hill Police Department's Investigation Bureau at (925) 288-4600.