A fixing device includes an endless belt-shaped fixing member; a pressing member; a contact member provided inside a loop formed by the fixing member and pressed against the pressing member via the fixing member to form a nip between the pressing member and the fixing member, a laminated heater facing an inner circumferential face of the fixing member to heat the fixing member, connected to an external power source, and including a heat generation sheet that includes a heat-resistant resin in which conductive particles to receive electricity from the external power source and generate heat are unevenly dispersed throughout the heat-resistant resin to have a dispersal gradient of increasing particle dispersion density from an inner face toward an outer face of the heat generation sheet; and a heater support to support the laminated heater along the inner circumferential face of the fixing member.