TECHNOLOGY FOCUS - POLYMERS - Preferred Resin: The resin (3) is a cross-linkable resin and contains repeating unit of formulae (1) and (2).Ar1 = bivalent group containing aromatic ring coupled with 1-20C linear or branched alkyl, hydrogen of aromatic ring is optionally substituted with alkyl, halogenated hydrocarbon or halogenX, Y = proton-acid group chosen from sulfonic acid group, carboxylic acid group, phosphoric acid group and sulfonimide group or their metallic saltsx, y = 0 or morex+y = 1 or moreThe resin (1) is formed by cross-linking proton-acid group-containing cross-linkable aromatic polyether ketone for 5 times by heat or irradiation of electromagnetic wave.Preferred Layer: The intermediate layer further contains resin (2) containing sulfonic-acid group-containing perfluoro carbon polymer compound.Preferred Composition: The content rate of resin (3) in the surface touching solid electrolyte film of intermediate layer is higher than that of surface touching diffusion electrode of intermediate layer. The coating liquid further contains resin (2).    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Particle: The catalyst particle consists of catalyst metal supported by electroconductive particle. EXAMPLE - 5,5'-carbonoyl bis (2-fluorobenzene sulfonic-acid sodium) (in g) (4.22), 4,4'-difluoro benzophenone (2.18), 2,2-bis (3,5-dimethyl-4-hydroxyphenyl)propane (5.69) and potassium carbonate (3.46) were mixed and reacted at 160 degrees C for 14 hours. Dimethyl-sulfoxide (40 ml) and toluene (30 ml) were further added and stirred under nitrogen atmosphere. The mixture was heated at 130 degrees C for 2 hours, and generated water was removed. Toluene was distilled and viscous polymer solution was obtained. The solution was filtered, precipitated and dried at 160 degrees C for 4 hours to obtain polymer powder (10.39) with yield of 92%. Sulfonic acid sodium-containing aromatic polyether ketone powder (0.5) was dissolved in dimethyl sulfoxide (100 ml). A soluble polymer compound of formula (A) was obtained. Catalyst supported carbon particle and sulfonic-acid sodium-containing aromatic polyether ketone powder were dipped in sulfuric acid in the ratio of 1:2 and water was distilled. The resulting mixture was dried at 160 degrees C for 4 hours, and sulfonic acid group-containing aromatic polyether ketone solution obtained using mixed solvent of tetrahydrofuran and water, was mixed. An intermediate layer coating liquid was obtained, and contained 5-10 wt.% of polymer concentration. A solid electrolyte film was obtained using the sulfonic acid sodium-containing aromatic polyether ketone powder, and had thickness of 50 microns. An electrode having catalyst layer containing ketone powder and catalyst particle, and carbon paper as a porous base material, was manufactured. A fuel cell having intermediate layer between solid electrolyte film and electrode, was manufactured. The fuel cell had favorable electric current voltage characteristics. The reduction of output of fuel cell was 5% or less even when continuous operation was performed for 1000 hours.