TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Compounds: The monomer (I) contains an aromatic vinyl monomer, (II) contains a vinyl monomer having an acidic group, (III) has a three-dimensionally basket-shaped structure in which a portion or all of silicon-oxygen, silicon-carbon and carbon-carbon bond, are bonded to carbon atom and (IV) contains an aromatic ring. Preferably (I) contains aromatic functional group (R1) having required number of carbon, (II) has hydrocarbon (R2) having ion conductive group, comprising ether, ester, acrylamide, amido and/or alkyl groups, sulfonic acid group, phosphoric acid and permissible heteroatoms (e.g. 2-acrylamide-2-methyl propane sulfonic acid and vinyl phosphoric acid) and (III) contains a bulk functional group in which silicon atom is bonded to cycloaliphatic carbon compound of required number member ring. (III) is a basket-shaped compound which is constructed by connecting a number of ring-shaped compounds which surround according to desired number of silicon and oxygen atoms by forming silicon - oxygen - silicon (Si-O-Si) bonds of facing silicon atoms through oxygen atoms. The fiber assembly is chosen from a cloth, a non-woven fabric, a fibril or a net of organic or inorganic fiber, and is copolymerized or cross-linked with the ionic conductive resin.Preferred Process: The vinyl monomer and cross-linking agent are polymerized by irradiating with cross-linking energy which is carried out by a heat conductor, infrared ray, far infrared radiation irradiation apparatus, under irradiation conditions such as fiber assembly impregnation temperature of 35-225degreesC for 0.5 seconds to 4 hours; or using ultraviolet ray or visualization photoirradiation device of wavelength 190-700 nm with vinyl monomer impregnation body surface of 0.5-5600 mW/cm2; or using electron beam irradiation apparatus which irradiates electron beam of 20-360 Mrad.m/minute for 0.2 seconds to 5 hours. SPECIFIC COMPOUNDS - The monomer (I) is t-butylstyrene, (II) is 2-acrylamide-methylpropane sulfonic acid, (III) is propyl methacrylic POSS and (IV) is bisphenol A glycerorate diacrylate.