NOVELTY - Polymer electrolyte fuel cell comprises: (1) a hydrogen ion-conductive polymer electrolyte film; (2) an anode and a cathode sandwiching the electrolyte film; (3) an anode side conductive separator having a gas passage which supplies fuel gas to the anode; and (4) a cathode side conductive separator having a gas passage which supplies oxidation gas to the cathode.    USE - Used as a polymer electrolyte fuel cell using hydrogen as a gaseous fuel or methanol, ethanol or dimethyl ether etc. as a liquid fuel and air or oxygen as an oxidizing agent.    ADVANTAGE - The viscosity of the catalyst ink is controlled without using a thickener by the solids concentration. The cell characteristics are improved by optimizing the water content of the electrode of the fuel cell.    DETAILED DESCRIPTION - Polymer electrolyte fuel cell comprises:    (1) a hydrogen ion-conductive polymer electrolyte film;    (2) an anode and a cathode sandwiching the electrolyte film;    (3) an anode side conductive separator having a gas passage which supplies fuel gas to the anode; and    (4) a cathode side conductive separator having a gas passage which supplies oxidation gas to the cathode.    The anode and the cathode at least comprises a catalyst layer which contacts with the electrolyte film and a gas diffusion layer which contacts with the catalyst layer and the separator, and includes an alkylene oxide compound.    At least one of the anode and the cathode includes a compound of formula R1-O-((C2H4O)n-(C3H6O)m)-R2 (I)    R1 - R2 = 5-15C alkyl group or H atom;    n = 0-5;    m = 0-5; and    n + m = 1-5, and when neither n nor m is 0, at least 1 ethylene oxide and at least 1 propylene oxide unit are randomly arranged.    An INDEPENDENT CLAIM is also included for the production of a polymer electrolyte fuel cell which comprises:    (1) forming a water-repellent ink comprising carbon powder and/or fibers, water repelling polymer, surfactant (I) and a dispersant;    (2) forming a catalyst ink including carbon particles supporting the catalyst powder, hydrogen ion-conductive polymer electrolyte and dispersant;    (3) forming a gas diffusion layer by coating the water repelling ink on a conductive porous substrate and evaporating the dispersant; and    (4) forming a catalyst layer from the catalyst ink.    DESCRIPTION OF DRAWING(S) - Figure 1 shows the electrolyte film-electrode assembly of the polymer electrolyte fuel cell.    Hydrogen Ion-Conductive Polymer Electrolyte Film (11)    Catalyst Layer (12)    Gas Diffusion Layer (13)    Electrode Pair (14)    Assembly (15)