The 18-year-old man had just made a delivery on Friars Way and was walking back to his car when he was approached by a knife-wielding man who demanded money.
The victim handed over his wallet, which is described as a black leather flip wallet with green stitching and the letter 'W' on it.
The incident happened opposite the council car park at around 8.15pm on Friday May 19, but police only released details today. (Mon May 22)
The suspect is described as a white man who was dressed in all black with his hood up. The lower part of his face was covered with tightly fitting black material.
Police are appealing to anyone who witnessed the incident or has any information about the suspect to contact them.
Anyone with any information asked to contact North Yorkshire Police on 101, quoting crime reference number 12170086373