A fixing device includes a rotatable cylindrical film, a contact member, a nip forming member, and regulating member. The regulating member includes an inner surface regulating surface that contacts and regulates a position of an inner surface of the film, and that, with respect to a rotational direction of the film, includes a first region remotest from a nip and a second region closer to the nip than the first region, the second region being positioned in a side upstream of a center of the nip with respect to a recording material feeding direction. The inner surface regulating surface is inclined so as to be spaced from the inner surface of the film toward a longitudinal center of the film, and a degree of inclination of the inner surface regulating surface is greater in the first region than in the second region.