A fixing device includes an endless belt that fixes toner onto a recording medium by heat, a heating member in the form of substantially a sheet that has flexibility and that heats the belt from inside a space enclosed by the belt, and a stationary member including a curved surface that is in contact with the heating member, a fixed area in the curved surface in which the heating member is fixed to the stationary member, and a non-fixed area in the curved surface in which the heating member is not fixed to the stationary member, the stationary member having a coefficient of linear expansion different from that of the heating member. The belt is wound around the stationary member via a layer that includes the heating member, and rigidities of the belt and the heating member are lower than a rigidity of the stationary member.