To provide a heating device that quickly raises a temperature of a matter to be heated such as resin material and moreover, prevents the occurrence of failure due to overheating of the matter to be heated.

When temperatures of a first heater 9, a second heater 10 and a third heater 11 are lower than a first temperature SV upon the starting of control of heater drive circuits 35, 36, 37 by means of a control part 31, a boot processing is performed. In the boot processing, the heater drive circuits 35, 36, 37 are controlled in such a manner that the temperatures of the first heater 9, second heater 10 and third heater 11 repeat the rise and drop between a second temperature SV+SV_ST(i)+dSV(i) that is set by adding a prescribed boot processing temperature SV_ST(i) and a prescribed temperature increase dSV(i) to the first temperature SV and a third temperature SV+SV_ST(i) that is set by subtracting the temperature increase dSV(i) from the second temperature SV+SV_ST(i)+dST(i).