A fixing device includes a cylindrical film including a heat generating layer and an electroconductive layer electrically connected with the heat generating layer. A volume resistivity of the electroconductive layer is less than a volume resistivity of the heat generating layer. The fixing device further includes an energizing member, a roller, a sliding member, and a supporting member. A thermal conductivity of the sliding member is greater than a thermal conductivity of the supporting member. A recording material on which a toner image is formed is heated while being fed through a nip. A longitudinal end of the sliding member is positioned between an inner end surface and an outer end surface of the electroconductive layer with respect to the longitudinal direction of the film.