NOVELTY - A liquid obtained by mixing metal alkoxide of metal chosen from magnesium, calcium, yttrium, aluminum, tin, titanium, zirconium, niobium, tantalum, and tungsten, and polydimethylsiloxane, is coated, dried at 70-210 degrees C, heated at temperature increase rate of 30-80 degrees C/minute, and maintained at 250-600 degrees C for 30-240 minutes. Thus, an organic-inorganic hybrid layer is obtained. The concentration of silicon at a depth of 1/4t and 3/4t from the surface of the organic-inorganic hybrid layer in the thickness direction satisfies specified relations.    USE - Manufacture of insulating film-coated metal foil used for solar cell substrate and flexible circuit substrate for mounting component in electronic device e.g. thin film transistor, organic electroluminescent display and electronic paper.    ADVANTAGE - The insulating film-coated metal foil has excellent surface flatness, pliability, insulating properties and thermal resistance. The hybrid layer of foil is prevented from scratching during conveyance and transportation. Solar cell and circuit are mounted at high yield.    DETAILED DESCRIPTION - A liquid obtained by mixing metal alkoxide of metal chosen from magnesium, calcium, yttrium, aluminum, tin, titanium, zirconium, niobium, tantalum, and tungsten, and polydimethylsiloxane, is coated, dried at 70-210 degrees C, heated at temperature increase rate of 30-80 degrees C/minute, and maintained at 250-600 degrees C for 30-240 minutes. Thus, an organic-inorganic hybrid layer is obtained. The concentration ((Si)1/4t) of silicon at a depth of 1/4t from the surface of the organic-inorganic hybrid layer in the thickness direction, and the concentration ((Si)3/4t) of silicon at a depth of 3/4t from the surface of the organic-inorganic hybrid layer in the thickness direction satisfies relations: (Si)1/4t less than (Si)3/4t, and ((Si)3/4t-(Si)1/4t)/(Si)3/4t=0.02-0.23. An INDEPENDENT CLAIM is included for insulating film-coated metal foil, which has organic-inorganic hybrid layer on one or both surfaces of metal foil.