TECHNOLOGY FOCUS - POLYMERS - Preferred Properties: The polymer (A) has fluidity at normal temperature and number average molecular weight of 500-20000. Preferred Composition: The fluorine-containing polymer composition further contains a hydrosilylation property compound (C). The compound (C) sets hydrosilylation reaction of polymer (A) having carbon-carbon double bond at both terminals, and is silicon hydride group-containing compound (C1) having two or more SiH group in the molecule. The compound (C) sets hydrosilylation reaction of polymer (A) having SiH group at both terminals, and is double bond-containing compound (C2) having two or more carbon-carbon double bond in the molecule. Preferred Compound: The compound (C) is hydrosilylation property polymer. The polymer is silicone rubber and/or fluoro silicone rubber which are liquid at normal temperature. EXAMPLE - Peroxide solution (4.6 ml) of 1,1,2-trichloro-1,2,2-trifluoroethane, hexafluoropropylene (10.9 g) and vinylidenefluoride (6.5 g) were mixed in a reactor substituted with nitrogen gas. The mixture was mixed at 20degreesC for 2.5 hours, and polymerized. The unreacted monomer and trifluoromethane were evaporated, to obtain a liquid polymer. The obtained polymer and trifluoroacetic acid were mixed and heated at 70degreesC for 2 hours. The reaction solution was washed with water and dried, to obtain liquid polymer (b). Allyl isocyanate (1 g) and polymer (b) (3.5 g) were reacted at normal temperature for 24 hours, and then heated at 100degreesC. The mixture was further heated at 100degreesC under pressure reduction. Excess allyl isocyanate was volatilized from the reaction mixture, to obtain polymer (c). The polymer had fluidity at normal temperature and number average molecular weight of 5400. The obtained polymer (c) was heat-processed at 180degreesC for 7 hours. The polymer (c) (1 g), HMS-301 (methyl hydro siloxane/dimethyl siloxane copolymer having molecular weight of 1900-2000) (0.0157 g) and toluene solution (0.008 g) of 0.06% platinum catalyst were mixed at 50degreesC for 2 hours, to obtain a liquid polymer composition. The composition was heated at 150-degreesC for 1 hour, to obtain a sheet-like cured material. The sheet had excellent mechanical strength.