PURPOSE: To prevent the deviation of a film without causing the peeling of a rib and the rupture of the film by adhering a specific hardness rib with a specific hardness adhesive on a device heating an image on a recording material via this endless film.

CONSTITUTION: A recording sheet passes on an entrance guide 8, and is fed between the film 2 and a pressurizing roller 9. A toner image on the recording sheet is heated and melted by the heat and pressure of a heating body 1 and the roller 9 and fixed on the recording sheet, and then, it is ejected by a paper ejecting roller 11 via a separating guide 10. The film 2 is a thin endless film formed with a heat - resistance resin base material such as polyimide, and the ribs 3a and 3b such as polyurethane having ≤ 100° JISA hardness, are adhered with the adhesive such as epoxy having ≤ 100° JISA hardness after it is hardened, on both ends of the film 2. Regulating members 12a and 12b are mounted inside the ribs, so that the deviation of the film 2 can be prevented.