A solid polymer fuel cell stack has a layered product comprised of a plurality of cells stacked, and is so structured that the layered product is fastened by end plates on both sides thereof via a current collector and an insulating plate on each side. Each cell is structured such that an MEA is sandwiched between an anode-side plate, which is provided with a fuel path disposed counter to an anode of the MEA, and a cathode-side plate, which is provided with an oxidizing agent path disposed counter to a cathode of the MEA. An MEA is comprised of a solid polymer electrolyte membrane, an anode and a cathode. The solid polymer electrolyte membrane is composed of powder of basic polymer such as polybenzimidazole, strong acid such as phosphoric acid impregnated with the basic polymer, and binder such as fluorocarbon resin.