A heating device including: a heat generating unit configured to receive an AC voltage from a power supply; a zero-crossing signal generating unit configured to generate a zero-crossing signal which is a square pulse signal synchronizing with a zero-crossing timing of the AC voltage, the zero-crossing signal being a first level at the zero-crossing timing and being a second level at other timings; and a control device configured to perform a detecting process in which an abnormality in a frequency or an output wave of the power supply or is detected, and an error processing, in a case where the abnormality in the frequency of the power supply or the abnormality in the output waveform of the power supply is detected and the level of a zero-crossing signal at a detection timing of detecting the abnormality is the second level.