A fixing apparatus includes: a pressing roller having a heating device therein; a metal roller having a core bar of metal; and a fixing roller that is set in contact with the pressing roller across a fixing belt wound around the fixing roller and the metal roller, has the width of the center portion formed in a cylindrical shape smaller than the width of the pressing roller, and has, at both ends, small-diameter rollers having a diameter smaller than the diameter of the center portion. Since stress is not applied to both ends of the fixing belt, the durable life of the fixing belt is extended.