To provide a heating device for raising a temperature of a heating chamber by the heat of a heater, capable of inhibiting the oxidation and deterioration of a heating element of the heater to prevent the shortening of the life of the heater.

This heating device comprises the heating chamber 1, the heater 2, a circulation fan 3, a temperature detecting sensor 4, a temperature control means 5 and a time control means 6. As the control temperature within a constant time Δt from the start of heating is kept low by the time control means 6, a heater temperature TH is not over a working limit temperature TX, which inhibits the progress of the oxidation and deterioration of the heating element of the heater, and the life of the heater can be prevented from being shortened.