A heating device includes an endless belt that rotates and a pressure rotator that rotates in a rotation direction. The pressure rotator contacts an outer circumferential surface of the endless belt to form a nip therebetween, through which a heating target having a particular width in an axial direction of the pressure rotator is conveyed. A heater includes a heat generator that defines a conveyance span in the axial direction of the pressure rotator, where the heating target is conveyed, and a non-conveyance span in the axial direction of the pressure rotator, where the heating target is not conveyed. A non-conveyance span temperature detector is disposed opposite the pressure rotator in the non-conveyance span of the heat generator. The non-conveyance span temperature detector detects a temperature of the pressure rotator.