A fixing device may include a nip member, an endless belt, a rotating body, and a stay. The endless belt may be in sliding contact with the nip member. The rotating body may nip the endless belt to constitute a nip region. The stay may be disposed opposite to the nip region, and may receive a pressure from the nip member. A pressure direction may be defined as a first direction. The rotating body may define an axial direction as a second direction. The stay may have a first wall. The first wall may include a center portion, a first end portion, a second end portion and a supporting portion. The first end portion may include a first low rigidity portion. The second end portion may include a second low rigidity portion. The supporting portion may provide a convex shape protruding toward the nip member upon receiving the pressure.