NOVELTY - A curable composition comprises a vinylidene fluoride elastomer or a tetrafluoroethylene-propylene type elastomer, a curing agent, and a compound which generates ammonia at 40-330 degrees C, and/or inorganic nitride particles. The vinylidene fluoride elastomer is a copolymer of vinylidene fluoride, perfluoroolefin(s) chosen from tetrafluoroethylene, hexafluoropropylene, and perfluoro(alkylvinyl ether), and monomer containing cyano group, carboxyl group, or alkoxycarbonyl group. The copolymerization ratio of vinylidene fluoride is greater than 20 mol%.    USE - Curable composition is used for heat-resistant components used as sealing materials for diffusion apparatus of semiconductor manufacturing apparatus, chemical vapor deposition apparatus, etching apparatus, waste-gas elimination apparatus, liquid-crystal manufacturing apparatus, solar-cell manufacturing apparatus, and organic-electroluminescent-element manufacturing apparatus (all claimed). Uses include but are not limited to O-ring, gasket, angle, rubber sheet, and joint sheet.    ADVANTAGE - The curable composition has excellent heat resistance, mechanical strength, chemical resistance, and cold resistance.    DETAILED DESCRIPTION - A curable composition comprises a vinylidene fluoride elastomer or a tetrafluoroethylene-propylene type elastomer, a curing agent, and a compound which generates ammonia at 40-330 degrees C, and/or inorganic nitride particles. The vinylidene fluoride elastomer is a copolymer of vinylidene fluoride, perfluoroolefin(s) chosen from tetrafluoroethylene, hexafluoropropylene, and perfluoro(alkylvinyl ether), and monomer containing cyano group, carboxyl group, or alkoxycarbonyl group. The copolymerization ratio of vinylidene fluoride is greater than 20 mol%. The tetrafluoroethylene-propylene type elastomer is a copolymer of tetrafluoroethylene (40-70 mol%), propylene (30-60 mol%), and monomer containing cyano group, carboxyl group, or alkoxycarbonyl group. An INDEPENDENT CLAIM is included for heat-resistant component obtained by hardening the curable composition.