To hold the fixing temperature of a fixing belt so as to shorten warm-up time and to improve fixing efficiency so as to make the quality of a fixed image higher by preventing the heat of the fixing belt heated by a heating roller from being taken away by a separated roller while the fixing belt is rotated.

By arranging a hollow pipe between the core roller and the outer circumference roller of the separated roller, the peeling roller is made a low heat capacity structural body, whereby the heat insulating effect of the separated roller is enhanced. Thus, warming-up is achieved at high speed and the fixable temperature in fixing is kept by restraining the temperature fall of the fixing belt though the fixing belt comes into contact with the separated roller.