A first region of a guide surface of a guide member, being in contact with an inner surface of a film on an upstream side of a heater in a rotation direction of the film, has a higher percentage of the protrusions per unit length in a longitudinal direction of the guide member than a second region of the guide surface, and the first and second regions are a region of the guide surface that overlaps a temperature detecting member and a region of the guide surface that does not overlap the temperature detecting member, respectively, in the longitudinal direction of the guide member.