It happened just after 9 pm at the 5-star Burger on Yosemite Parkway and Marthella Avenue.
Police said the armed suspect came up to the ordering window, pulled out a gun and demanded cash from the employee.
The suspect took the money and then ran away. No one was hurt.
A photo from a surveillance camera released by Merced police shows the suspect in a black hooded sweatshirt and mask.
Anyone with information is asked to call the Merced Police Department.
