PURPOSE: To prevent the destruction or combustion of the place concerned by estimating the temp. of the part where the direct contact with a thermistor is impossible by performing calculation on the basis of the respective temps. at a plurality of parts detected by thermistors to control the rotation of a fan motor.

CONSTITUTION: A recording apparatus is constituted of a thermal fixing device constituted of a heater 32, a fan motor 38 for lowering the temp. in the apparatus, a plurality of thermistors 33, 34, 36 detecting the temps of a plurality of the parts of the thermal fixing device, A/D converters 504-506 detecting a plurality of voltage values changing corresponding to resistance values of the respective thermistors 33, 34, 36 and a CPU 507. The CPU 507 performs calculation on the basis of the respective detected temps. at a plurality of the parts to control the rotation of the fan motor 38. By this constitution, the temps. of parts where the direct contact with the thermistors is impossible are estimated and the fan motor 38 is rotated on the basis of the estimated results to prevent the destruction or combustion of the place concerned.