A fixing device includes a heater and a presser. The heater includes an endless heating belt that rotates while heating a recording medium carrying an unfixed toner image. The presser presses against the recording medium in cooperation with the heater to fix the unfixed toner image onto the recording medium. The heater further includes a first plate body extending to form a contact region in contact with an inner surface of the belt, a heat source nipping the first plate body in cooperation with the belt in the contact region, and a second plate body disposed opposite the first plate body with the heat source interposed therebetween and extending at a distance from the heat source. The first plate body has relatively higher heat absorptivity than the second plate body. The second plate body has relatively higher heat reflectivity than the first plate body and is in contact therewith.