To provide a belt type fixing device for an image forming device capable of realizing the shortening of by time for start-up, low power consumption, the reduction of cost and stable image fixation over a long term.

In this belt type fixing device for the image forming device equipped with an endless fixing belt for fixing an image, a carrying roller rotatably supporting the fixing belt, and a heat source for heating the fixing belt and a pressure roller pressing paper to the fixing belt; the fixing belt is formed of heat resistant releasing material being a single layer, and provided with a belt reinforcing member for reinforcing the fixing belt on the outer peripheries or the inner peripheries of both ends.