To provide a heating device that can accurately control a temperature changing speed of material to be heated such as resin material.

A procedure for changing the temperature of a heater 5 to the final temperature target value SV is divided into a plurality of large steps and a target value TS_1ST of the temperature change speed of the heater 5 at each large step is set. Further, each large step is divided into a plurality of small steps and a target value TS_2ST of the temperature change speed of the heater 5 in each small step is set. Therein, temperature of the resin material is detected by a temperature sensor 7 and, on the basis of the detection temperature, the temperature of the heater 5 is controlled to be changed at the target value TS_2ST in each small step. Further, the temperature of the heater 5 is controlled to be changed at the target value TS_1ST in the large step.