A heating device includes a substrate having first and second surfaces, a plurality of heating elements each disposed in one of a central region and end regions of the first surface of the substrate, a heat conductor layer on the second surface of the substrate, a plurality of thermometers arranged on the heat conductor layer and each configured to measure a temperature of one of the central region and the end regions, and a plurality of thermostats arranged on the heat conductor layer and each configured to measure the temperature of one of the central region and the end regions and interrupt electrical power supplied to the heating element disposed in said one of the central region and the end regions when the measured temperature exceeds a predetermined value. The thermometers and the thermostats are alternately arranged on the heat conductor along a longitudinal direction of the heat conductor layer.