NOVELTY - Membrane-electrode structure is produced by applying on a sheet substrate a catalyst paste having electron conducting material supporting a catalyst and ion conducting material, and drying sheet substrate to form electrode catalyst layer (3); and thermally transferring the electrode catalyst layer into each side of polymer electrolyte membrane (1) to form laminated body.    USE - For producing membrane-electrode structure used in polymer electrolyte fuel cell. The polymer electrolyte fuel cell is used in an electrical apparatus and transport machine. (All claimed)    ADVANTAGE - The invention provides membrane-electrode structure having excellent adhesiveness between electrode catalyst layer and diffusion electrode.    DETAILED DESCRIPTION - Production of membrane-electrode structure comprises applying on a sheet substrate a catalyst paste having electron conducting material supporting a catalyst and ion conducting material, and drying sheet substrate to form electrode catalyst layer; thermally transferring the electrode catalyst layer into each side of polymer electrolyte membrane to form laminated body so that the electrode catalyst layer is connected to each side of the polymer electrolyte membrane; applying on a carbon substrate layer a first slurry having water-repellent material and electron conducting material, drying the carbon substrate layer to form a water-repellent layer, applying on the water-repellent layer a second slurry having electron conducting material and ion conducting material, and drying the water-repellent layer to form hydrophilic layer to form diffusion electrode having carbon substrate, water-repellent layer, and hydrophilic layer; and laminating the diffusion electrode on the electrode catalyst layer of the laminated body through the hydrophilic layer, and pressing the two under heating to integrate the laminated body and diffusion electrode.    DESCRIPTION OF DRAWING(S) - The figure schematically shows an example of the production of a membrane-electrode structure.    Polymer electrolyte membrane (1)    Fluorine mold releasing film (2)    Electrode catalyst layer (3)