NOVELTY - A composite film structure comprises hydrogen permeability metal film (1) and solid electrolytic membrane (2) which is formed by coating method on surface in which hydrogen permeability metal film is thermally oxidized, wherein bivalent alkaline-earth metal is arranged on A site and consists of compound which has crystal structure which makes basic structure a perovskite-type oxide which arranges tetravalent cerium and/or tetravalent zirconium to B site and substitutes tetravalent B site elements by trivalent rare earth elements.    USE - A composite film structure for fuel cell (claimed).    ADVANTAGE - Composite film structure has excellent hydrogen permeability and electrochemical characteristics, such as electroconductivity.    DETAILED DESCRIPTION - A composite film structure comprises hydrogen permeability metal film (1) and solid electrolytic membrane (2) which is formed by coating method on surface in which hydrogen permeability metal film is thermally oxidized, wherein bivalent alkaline-earth metal is arranged on A site and consists of compound which has crystal structure which makes basic structure a perovskite-type oxide which arranges tetravalent cerium and/or tetravalent zirconium to B site and substitutes tetravalent B site elements by trivalent rare earth elements, solid electrolytic membrane coats alkaline-earth metal and organometallic acid salt solution consists of cerium and/or zirconium and forms 1st solid electrolyte precursor membrane, and 1st solid electrolytic membrane is formed by crystallizing 1st solid electrolyte precursor membrane with rapid temperature rising heat processing. INDEPENDENT CLAIMS are included for:    (1) fuel cell containing composite film structure in which surface on opposite side to hydrogen permeability metal film of is equipped with cathode, and hydrogen permeability metal film becomes an anode; and    (2) manufacturing method of composite film structure which involves performing thermal oxidation process of surface of hydrogen permeability metal film, arranging bivalent alkaline-earth metal at A site on surface in which hydrogen permeability metal film is thermally oxidized, forming solid electrolytic membrane consists of compound which has crystal structure which makes basic structure a perovskite-type oxide which arranges tetravalent cerium and/or tetravalent zirconium to B site and substitutes tetravalent B site elements by trivalent rare earth elements, forming 1st solid electrolytic membrane according by coating organometallic acid salt solution containing rare earth elements to form solid electrolyte precursor membrane, heating solid electrolyte precursor membrane at less than or equal to 900 degrees C with rapid temperature rising heat processing, and crystallizing.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic diagram of a composite film structure. (Drawing includes non-English language text).    Hydrogen permeability metal film (1)    Solid electrolytic membrane (2)