PURPOSE: To reduce the complication of a temperature control sequence for a heating body by installing plural heaters on the heating body, selectively controlling the power supply to the heaters and executing the temperature rise-up control and the thermostatic control of the heating body.

CONSTITUTION: A 1st heater driving signal S1 is transmitted so as to turn on a 1st TRIAC 7. When the 1st TRIAC 7 is turned on, a power is supplied from an AC power source 12 to a rise-up heating heater 3 for the heating body. Thus, the heat is generated by the heater 3, then, the temperature of the heating body is rapidly raised. When it is detected by a CPU 11 that the temperature of the heating body rises up to a prescribed fixation temperature, the 1st heater driving signal S1 is turned off, and a 2nd heater driving signal S2 is turned on. Then, the 1st TRIAC 7 is turned off, so that the power is not supplied to the heater 3, but, a 2nd TRIAC 8 is turned on instead of the TRIAC 7, then, the power is supplied from the AC power source 12 to a thermostatic control heater 4 for the heating body.