TECHNOLOGY FOCUS - POLYMERS - Preferred Composition: The ion exchange capacity of the ion exchange resin of (3) is larger by 0.01 - 1.5 meq./g dry resin than (4). The weight proportions of the catalyst and the ion exchange resin in (5) are such that the catalyst:the ion exchange resin is 0.40 - 0.95:0.05 - 0.60. Preferred Polymer Electrolyte: (2) is preferably a perfluorosulfonic acid ion exchange resin, perfluorophosphonic acid ion exchange membrane, partially fluorinated sulfonic acid ion exchange membrane, partially fluorinated phosphonic acid ion exchange membrane, non-fluorinated hydrocarbon sulfonic acid type ion exchange membrane or non-fluorinated hydrocarbon phosphonic acid ion exchange membrane. Preferred Ion Exchange Resin: (6) is preferably a fluorocarbon sulfonic acid ion exchange resin or a fluorocarbon phosphonic acid ion exchange resin. Preferred Component: (3) and (4) present in (1) contains a soluble perfluorocarbon polymer(7) as a water repellant. (7) is a thermoplastic polymer having repeating units of the following formulaen = 1 or 2. EXAMPLE - A catalyst having 40 wt.% of platinum supported on carbon black powder and solutions in ethanol of ion exchange resins were prepared. The weight proportions of the catalyst and the ion exchange resin in the dispersion was 0.80:0.20. The ion exchange capacity (meq./g dry resin) of the ion exchange resin for the fuel electrode was 1.1 and for the air electrode was 0.91. Flemion S membrane(perfluorosulfonic acid type ion exchange membrane, ion exchange capacity = 1.0 meq./g dry resin, thickness = 80 mum) was added to the above catalyst dispersion and the solution was sprayed so that the amount of platinum in a fuel electrode and an air electrode would be 1 mg/cm2 and membrane electrode assembly(MEA) was obtained. Each of such MEA was assembled into a cell and continuous operation was carried out at a constant driving voltage of 0.65v and a cell temperature of 70degreesC at 3 ata in a hydrogen/air system. The output current density (A/cm2) for the test invention/comparative after 10, 500 and 1000 hours was 0.92/0.81, 0.78/0.50 and 0.65/0.28.