NOVELTY - An electrolytic membrane (1) contains proton-conductive material (2) (A), and proton-conductive material (3) (B). The proton-conductive material has self-film-formability.    USE - Electrolytic membrane is used for electrolytic membrane-catalyst layer composite material, electrolytic membrane-electrode assembly of fuel cell (all claimed) such as polymer electrolyte fuel cell and direct methanol fuel cell.    ADVANTAGE - The electrolytic membrane has high dimensional stability, gas barrier property, mechanical strength, heat resistance, proton conductivity, and water retention. The fuel cell comprising electrolytic membrane-electrode assembly has improved electric power generation performance. In direct methanol fuel cell, crossover of methanol aqueous solution from anode side to cathode side is suppressed. Thus, reduction of electric power generation performance is prevented.    DETAILED DESCRIPTION - An electrolytic membrane contains proton-conductive material (A) (2-50 wt.%), and proton-conductive material (B) (50-98 wt.%). The proton-conductive material has self-film-formability. The proton-conductive material (A) is fluorine type proton-conductive polymeric material, hydrocarbon type proton-conductive material, inorganic proton-conductive material, and/or organic-inorganic matter hybrid proton-conductive material. The proton-conductive material (B) is fluorine type proton-conductive polymeric material, hydrocarbon type proton-conductive material, inorganic proton-conductive material, organic-inorganic matter hybrid proton-conductive material, and/or ionic liquids. An electrolytic membrane-catalyst layer composite material consists of catalyst layer containing catalyst particles and electrolyte binder.    DESCRIPTION OF DRAWING(S) - The drawings show perspective view, top view, and sectional view of proton-conductive material (A), and cross-sectional view of electrolytic membrane.    Electrolytic membrane (1)    Proton-conductive material (2)    Proton-conductive material (3)