A fixing device includes a belt, a roller, a heater, and a reflector. The belt is rotatable in a rotational direction. The roller is positioned to be in contact with an outer peripheral surface of the belt so as to form a nip between the roller and the belt. The heater is disposed within an inner circumference of the belt. The reflector is disposed within the inner circumference of the belt. The reflector includes a first portion and a second portion. The first portion is in contact with and protrudes outwardly the belt at a first region downstream with respect to the nip in the rotational direction. The second portion is configured to reflect heat generated by the heater toward an inner surface of the belt at a second region upstream with respect to the nip in the rotational direction.