It happened at Auto Discounts on Regent Parade between 5.30pm yesterday and 7am this morning.
North Yorkshire Police say the front window of the store was smashed and the bike was stolen from the window display.
It is a Raleigh Helion 2.0 Mens mountain bike in blue, with front suspension.
Police are asking for the public to help with investigations and are appealing for information about the incident and whether anyone has been seen acting suspiciously in that area.
A spokesperson added: "We are also interested to know if anyone has seen a push bike like the one stolen for sale since the incident."
Anyone with information contact North Yorkshire Police on 101, select option 2, and ask for PC COOKE 663 or email [email protected]
If you wish to remain anonymous, you can pass information to Crimestoppers on 0800 555 111. Quote the North Yorkshire Police reference number 12180067306