A fixing apparatus according to the invention is provided with a heating roller 2 including an elastic member 2b and a metal conductive layer 2c. The elastic member has a greater outer diameter at its end portions than at its central portion. At least one air hole 100 is formed through the metal conductive layer 2c at a predetermined position opposing the small-diameter central portion of the elastic member. The air hole connects the outside to a clearance formed between the elastic member 2b and the metal conductive layer 2c.