TECHNOLOGY FOCUS - POLYMERS - Preferred Composition: The catalyst composition further contains perfluoro-alkyl sulfonic acid type polymer. The weight ratio of aromatic polymer with respect to metal catalyst is 0.01-100, and the weight ratio of carbon microparticle with respect to metal catalyst is 0.01-100.Preferred Component: The aromatic polymer has structure of formula: -(A-Z)m-(A'-Z')n-.A = bivalent aromatic group chosen from formulae (3a)-(3c)A' = bivalent aromatic group substituted with highly acidic group chosen from formulae (3d)-(3g)Z, Z' = direct bond or bivalent group preferably -O-, -S-, -CO-, -SO2-, 1-12C alkylene, 1-12C alkylene dioxym = 0-100000n = 10-100000R = hydroxyl, 1-6C alkyl, 1-6C alkoxy, 7-12C aralkyl, aryl or halogenp, r, s, t = 0-4q = 0-6j = 0 or 1Y = direct bond or bivalent group preferably -O-, -S-, -CO-, -SO2- or fluorine substituted 1-20C alkylene, 1-20C alkylene dioxy, 6-12C arylene, 6-12C arylene oxy or 1-20C alkylene oxyD = highly acidic grouph' = 1-4p'+h, r'+h, s+h''' = 1-6q'+h' = 0-4h, h''' = 1-6Preferred Group: The highly acidic group is chosen from formulae (2a)-(2d):-G-SO3-W+ (2a)-G-SO2N-W+SO2-E (2b)-G-P(O)-(O-W+)2 (2c)-G-P(O)-O-W+-E (2d)G = alkylene, aralkylene or arylene partially substituted with fluorineW+ = positive ion preferably hydrogen ionE = alkyl, aralkyl or aryl partially substituted with fluorine    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Component: The metal catalyst is contains platinum or alloy having platinum as essential component. EXAMPLE - Poly(oxy-4,4'-biphenylene oxy-4,4'-diphenyl sulfone) (in g) (15) was dissolved in methylene chloride (80 ml). Bromine (46.5) was added at 0 degrees C to the reaction mixture for 10 minutes, and the mixture was stirred at room temperature for 4 hours. The resultant reaction solution was added to aqueous solution of hypo. The reaction solution was distilled under pressure, and polymer having bromo group in the phenyl ring was obtained. The obtained polymer had number average molecular weight of 34000. The obtained polymer (0.5), copper powder (500), and N,N-dimethyl sulfoxide (10 ml) were mixed and stirred at 120 degrees C for 2 hours in nitrogen atmosphere. Subsequently N,N-dimethyl sulfoxide solution of 5-iodo-octafluoro-3-oxa pentane potassium sulfonate (1) was added to reaction solution at 120 degrees C. Reaction was performed for 40 hours, and catalyst composition was obtained. The obtained composition provided fuel cell having excellent electric power generation capability.