The invention provides a fuel cell which comprises a cathode and an anode arranged to sandwich a proton-conductive ion exchange electrolytic membrane, oxygen and hydrogen containing carbon monoxide being supplied to the cathode and the anode, respectively, in which the cathode comprises an electroconductive porous substrate which carries thereon platinum or a platinum alloy and a proton-conductive ion exchange electrolytic polymer, and the anode comprises an electroconductive porous substrate which carries thereon platinum or a platinum alloy and a proton-conductive ion exchange electrolytic polymer, and further at least the anode carries a proton-supplying material thereon.