TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Film: The sulfonic acid group is covalently bonded with silicon atom through 20C or less linear alkylene group. Preferred Property: The ratio of pores having pore size of 2-10 nm is 80% or more and that of pore size 10-100 nm is 20% or less with respect to total pore volume. A shoulder or a scattering peak is observed in the range of 2 theta=6-23degrees by X-ray diffraction. The condensation degree of silicon-oxygen cross-linked structure is 85% or more by 29Si-NMR analysis.    TECHNOLOGY FOCUS - POLYMERS - Preferred Material: The polymeric material is a fluorine group polymer material which consists of polytetrafluoroethylene, and has film thickness of 20-100 microns, pore size of 0.05-0.2 microns and porosity of 60% or more. The porous material is subjected to hydrophilization treatment by adding a silane coupling agent such as epoxy silane and/or amino silane. The fluorine material having hydrophilic group including hydroxyl group on its surface, is immersed in metallic sodium naphthalene complex-containing liquid. EXAMPLE - X-41-1805 (3-mercapto propyl trimethoxy silane and tetraethoxy silane) (in g) (0.8), tetraethoxy silane (0.3) and polyethylene glycol (0.08), were provided in a beaker. Diethyl amine (0.3), 1 wt.% potassium fluoride methanol solution (0.12) and water (0.3) were provided in another beak mer. The catalyst and water solution were added to the beaker containing silane raw material and hydrolyzed uniformly. The liquid mixture was poured on a petri dish of fluorine resin and gelatinized. The gelatinized film was provided in 80% oven for 2 hours at 270degreesC. The obtained membranous substance was immersed in 1N hydrochloric acid solution and water at 80degreesC for 1 hour. The unreacted substance, catalyst and polar controlling agent were removed from the film. The film was then immersed in 125 ml of acetic acid and peracetic acid containing hydrogen peroxide solution and heated at 80degreesC for 1 hour. The peracetic acid solution was extracted and a transparent hard film was obtained. The proton conductive film had thickness of 200 microns.