A fixing apparatus is provided to set a heat transfer path of a radiation unit clearly, thereby increasing heat efficiency. A cylindrical heating unit(210) generates heat. A fixing device(200) fixes toner powder by transferring radiant heat of the heating unit through a heat transferring unit(220) between an inside barrel(250) and an outside barrel(260). The heater and the inside barrel comprise the first medium unit maintaining a predetermined straight distance, and the second medium unit of a predetermined number between the inside barrel and outside barrel. The first medium unit and the second medium unit are filled with a liquid medium which has a coefficient of heat conduction of 1W /m-k or greater at least.
