PURPOSE: To perform a consecutive copying in a copying machine and to perform copying at high speed, by recognizing temperature status in the periphery of a fixing part, controlling the copying speed of the copying machine based on the result, and performing the driving control of a fan to cool the inside of the copying machine.

CONSTITUTION: In a device which performs the temperature control of the copying machine by performing the ON/OFF control of a heater 4 provided at the fixing part 2, the ON/OFF control of the heater 4 is performed based on the detected result of a temperature sensor which detects the surface temperature of a fixing roller 3 mounted at the fixing part 2. And the driving of the copying machine which sets the copying speed is controlled based on the detected result of a duty factor detecting part 12 which detects a duty factor corresponding to the ON/OFF interval of the heater. Furthermore, the driving control of the fan to perform the cooling of the fixing part 2 is performed. In such a way, it is possible to realize the consecutive copying, and to improve the operability of the copying machine remarkably.