To improve the margin of temperatures for good fixability and breaking temperatures of a fixing device by using a heater with high thermal efficiency in the state that the quantity of heating element paste on the heater is efficiently reduced, and by decreasing the temperature difference between a paper feeding area and a paper non-feeding area in the longitudinal direction of the fixing device, and to reduce the cost of a heating body.

In the heating body used for a heat pressure type fixing device, the heating body has a plurality of conductors vertically extending against the introducing direction of a heated material in the introducing direction, resistors are formed between the conductors, and the resistors are thinned out.