A low-radiation-rate film, made of a material whose radiation rate is lower than that of a heater substrate, is formed at least entirely over the surface of a heat-subject-placing surface of a heater substrate. By applying patterning to the low-radiation-rate film, the exposure rate of the heater substrate is varied such that the radiation rate becomes smaller from the center part of the heat-subject-placing surface toward the outer peripheral part thereof, thereby enabling a uniform temperature across the surface. In addition, the power supply is reduced, thermal stress is eliminated, the wiring design flexibility is increased, and the reliability is increased by preventing short-circuit accidents.