In order to provide a membrane electrode assembly and a fuel cell in which the thickness of the solid polymer electrolyte membrane is thin by enhancing self-protection of the solid polymer electrolyte membrane, a membrane electrode assembly comprises a solid polymer electrolyte membrane and a pair of gas diffusion electrode layer having catalyst layers and gas diffusion layers. The catalyst layers of the gas diffusion electrode layer sandwich the solid polymer electrolyte membrane, one surface of the solid polymer electrolyte membrane is covered by the gas diffusion electrode layer and the other surface of the solid polymer electrolyte membrane extends over the gas diffusion electrode layer, and ends of the catalyst layer of one gas diffusion electrode layer are disposed to be offset to ends of the catalyst layer of the other gas diffusion electrode layer.