A fixing device includes an endless fuser belt, a contact member, a pressure member, a heater, a first thermometer, a second thermometer, and a controller. The fuser belt is looped into a generally cylindrical configuration. The contact member extends inside the loop of the fuser belt. The pressure member extends with the fuser interposed between the contact member and the pressure member. The pressure member is pressed against the contact member through the fuser belt to form a fixing nip. The heater includes a first heating element and a second heating element. The first heating element heats the fuser belt at a first position. The second heating element heats the fuser belt at a second position. The first thermometer detects a first temperature of the fuser belt. The second thermometer detects a second temperature of the fuser belt. The controller controls each of the first and second heating elements.