A fixing device includes a conductive and magnetic hollow roller, a metallic layer made of high thermal conductive material formed on the outer surface of the hollow roller, and a magnetic field generating coil provided in the hollow roller to generate eddy current on the hollow roller. A power source applies high-frequency current to the magnetic field generating coil and a pressure roller contacts the hollow roller in a specified nipping width. Also provided is a fixing device with a second hollow roller fitted to the outer surface of a first hollow roller, a coil provided in the first hollow roller, a current source for selectively applying current of at least two frequencies, and a third roller contacting the second roller in a specified nipping width.