Officers say they hope he can assist them with their inquiries into the assault, which happened in a Glasgow shop.
Authorities sent out the photograph from CCTV footage inside the Sauchiehall Street branch of Poundland.
The incident took place at around 5.15pm on Friday, May 30, and extensive inquiries are currently under way.
Detectives directly appealed for the man in the footage to contact them as it is believed he may have witnessed the incident or have information that can help with the investigation.
He is described as Asian appearance, between 40 and 49, around 6ft, and of medium build.
Police said he was wearing a white baseball cap, glasses, navy blue jacket, light coloured body warmer, and a blue T-shirt.
He also wearing dark denim jeans, with the bottoms turned up, and he was carrying a khaki backpack.
Police hope the distinctive description will help in quickly identifying the man.
Inspector Kenny Darroch, who is leading the inquiry into the incident, appealed for witness to come forward.
He said: "I would appeal to anyone who was in Poundland on Sauchiehall Street around the time of the incident to contact officers.
"I would also ask anyone who can help identify the man in the image to contact Baird Street Police Office on 101."
No further details, including the girl's age, could be released by officers.
Meanwhile, investigations are continuing into a sex attack on a 24-year-old woman in Govanhill.
She was attacked in Dixon Road, in the early hours of Monday, May 19. Anyone with any information is asked to contact Police Scotland on 101.