NOVELTY - A polymer electrolyte fuel cell has a pair of electrodes sandwiching a hydrogen ion conductive polymer electrolyte membrane. Each electrode has an electrode catalyst layer comprising conductive carbon particles carrying electrode catalyst particles and a hydrogen ion conductive polymer electrolyte. At least one of the electrodes comprises a catalyst for trapping fuel gas or oxidant gas.    USE - Polymer electrolyte fuel cell.    ADVANTAGE - The fuel cell maintains high power generation efficiency over an extended period even when the humidity of the oxidant gas supplied is low. The fuel cell suppresses deterioration of hydrogen ion conductive polymer electrolyte in the polymer electrolyte membrane and catalyst layers.    DETAILED DESCRIPTION - A polymer electrolyte fuel cell comprises a hydrogen ion conductive polymer electrolyte membrane (21), a pair of electrodes (27, 28) sandwiching the polymer membrane, a first separator plate having gas flow path for supplying fuel gas to one of the electrodes and a second separator plate having a gas flow path for supplying oxidant gas to the other electrode. Each electrode has an electrode catalyst layer (22, 23) comprising conductive carbon particles carrying electrode catalyst particles and a hydrogen ion conductive polymer electrolyte. The electrode catalyst layer is in contact with the polymer electrolyte membrane. At least one of the electrodes comprises a catalyst (24) for trapping fuel gas or oxidant gas which has passed through the polymer electrolyte membrane from the other electrode toward the electrode catalyst layer of the one of the electrodes.    An INDEPENDENT CLAIM is also included for fabrication of polymer electrolyte fuel cell by:    (i) coating a catalyst for promoting reaction of hydrogen and oxygen with hydrogen ion conductive polymer electrolyte;    (ii) mixing the coated catalyst with an electrode catalyst and dispersion medium to prepare an ink; and    (iii) forming an electrode catalyst layer from the ink.    DESCRIPTION OF DRAWING(S) - The figure is a longitudinal section of a membrane-electrode assembly.    Hydrogen ion conductive polymer electrolyte membrane (21)    Catalyst layers (22, 23)    Trapping catalyst (24)    Electrodes (27, 28)