A fuel can adapter has a threaded section for threadly engaging with a fuel device. Particularly, the fuel device has a threaded joint for engagement with the thread section of the fuel can adapter. In addition, this threaded joint can be used to connect a fuel can with a thread head, such that fuel in the fuel can can flow to the fuel device. With the fuel can adapter, a fuel can with a head, which does not have a threaded head but has a flange extending circumferentially thereon, is adapted to connect to the fuel device, such that fuel in the fuel can can flow to the fuel device.