According to one embodiment, a fixing device fixes a toner image formed on a medium to the medium. The fixing device includes a heating rotator which is rotatably supported, an auxiliary heating member which is disposed along an inner circumferential surface of the heating rotator, and swings as the heating rotator rotates, a lubricant supply member which is disposed at a position on which the swing auxiliary heating member abuts, and is impregnated with a lubricant, and a pressing rotator which abuts on the heating rotator, and forms a nip portion through which the medium passes.