PURPOSE: To prevent a radiation from a driving gear, to raise a thermal efficiency of a heating roller, and also to prevent a driving part peripheral apparatus from becoming a high temperature by forming coaxially and as one body the driving gear of the roller and its shaft supporting part by using a heat insulating material.

CONSTITUTION: A metallic flange part 12 on which a shaft supporting part 14 and a driving gear 15 are formed coaxially and as one body by using a heat insulating material is fixed to the side end part of a heating roller 11. Also, the shaft supporting part 14 is installed into a bearing 13 fitted to supporting metallic fittings 13a, and the driving gear 15 is engaged to a gear 15a connected to a driving device. According to such a constitution, it is prevented that a heat capacity from the driving gear 15 is radiated a thermal efficiency of the heating roller 11 is raised, and also it is prevented that a driving source peripheral apparatus becomes a high temperature.