TECHNOLOGY FOCUS - POLYMERS - Preferred Monomer: The fluoromonomer A is a perfluoromonomer and fluoromonomer B is same as fluoromonomer D.Preferred Properties: The solid polymer electrolyte material has an ion exchange capacity of 0.5-2.5 meq/g dry resin. The -SO2X group at the terminal of the repeating unit based on the fluoromonomer B, is a -SO3H group, which is useful as a material constituting a solid polymer fuel cell. The copolymer of solid polymer electrolyte material has a softening temperature of 100degreesC. Preferred Definitions:    M = H.    SPECIFIC COMPOUNDS - The fluoromonomer A is selected from perfluoro(3-butenyl vinyl ether), perfluoro(2,2-dimethyl-1,3-dioxole), perfluoro(1,3-dioxole), 2,2,4-trifluoro-5-trifluoromethoxy-1,3-dioxole and perfluoro(2-methylene-4-methyl-1,3-dioxolane), preferably perfluoro(2,2-dimethyl-1,3-dioxole).    EXAMPLE - A nitrogen purged autoclave was charged with perfluoro (2,2-dimethyl-1,3-dioxazole) (PDD) (in g) (26.0), CF2=CFOCF2CF(CF3)OCF2CF2SO3H (127.8) (PSVE-H) and (CH3)2CHOC(=O)OOC(=O)OCH(CH3)2 (IPP) and polymerized. The obtained polymer was diluted, poured into hexane and precipitated. The polymer had average molecular weight of 56000. The obtained polymer was hydrolyzed, dissolved in ethanol and a transparent ethanol solution containing 10 mass% of the polymer PDD/PSVE-H was obtained. A platinum supported carbon (PSC) was dispersed in the obtained ethanol solution, dried and pulverized. The obtained powder was re-dispersed in 2,2,3,3,3-pentafluoro-1-propanol and a coating liquid for forming catalyst layer of cathode was obtained. PSC was mixed and dispersed in ethanol solution of tetrafluoroethylene (TFE)/PSVE-H copolymer obtained using TFE and PSVE-H, and a coating liquid was obtained for forming catalyst layer on anode. A water repellent carbon powder layer was loaded on water repellent carbon cloth, hot pressed and a catalyst layer was formed. The coating liquids for forming catalyst layers of cathode and anode were coated on water repellent carbon powder layer and dried to form respective electrode catalyst layers. The cathode and anode were cut and interposed with a polymer electrolyte membrane made of sulfonic acid type perfluorocarbon polymer FLEMION HR, bonded and a membrane electrode assembly was obtained. A separator made of carbon and having a gas flow path was mounted to obtain a cell for measurement. A current voltage characteristics test of the cell was carried out. Cell voltages upon expiration of 10 hours from the initiation of the operation at 0.3 A.cm-2 and 1 A.cm-2 were 820/mV and 725/mV respectively.