A pressurizing member includes an elastic member having a uniform elastic modulus of K=EA/t, where E is a Young's modulus, A is an area of the nip portion, and t is a thickness of the elastic member in the direction of application of load. A supporting member that supports the pressurizing member has an entering portion, an exit portion, and a center portion between the entering portion and the exit portion. The thickness of the center portion in a direction of application of load is larger than thicknesses of the entering portion and the exit portion in the direction of application of load so that the supporting unit has a convex portion.