NOVELTY - A hardenable fluoropolyether-type rubber composition contains (in parts mass) linear perfluoropolyether compound (A) (100) having alkenyl groups and bivalent perfluoroether structure having fluorine-containing repeating unit (I), fluorine-containing organosilicon compound (B) having hydrogen atoms bonded with silicon atom, hydrosilylation reaction catalyst (C) and silica fine powder (D) (10-40). The surface of silica finer powder is hydrophobilized by alkyl-containing silicon compound, vinyl-containing silicon compound and perfluoroalkyl group-containing silicon compound.    USE - Hardenable fluoropolyether-type rubber composition is used for O-ring for quick connector and injector. Uses include but are not limited to diaphragm for motor vehicle, valve for canister and power control, gasket for cylinder head, sealing material for fuel cell, inkjet printer, roll material of copier, potting material for sensor, coating material and extrusion component.    ADVANTAGE - The hardenable fluoropolyether-type rubber composition has excellent heat resistance, chemical resistance, solvent resistance, water repellence, oil repellence and low-temperature characteristics, and provides cured material with improved compression set property with respect to ethylene glycol aqueous solution.    DETAILED DESCRIPTION - A hardenable fluoropolyether-type rubber composition contains (in parts mass) linear perfluoropolyether compound (A) (100) having 2 or more alkenyl groups in a molecule and bivalent perfluoroether structure having fluorine-containing repeating unit (I) in a principal chain, fluorine-containing organosilicon compound (B) having 2 or more hydrogen atoms bonded with silicon atom in a molecule, hydrosilylation reaction catalyst (C) and silica fine powder (D) (10-40) having Brunauer Emmett Teller specific surface area of 50 m2/3 or more. The linear perfluoropolyether compound (A) has number average molecular weight of 3000-100000. The ratio of silane group (SiH) and alkenyl group in the fluorine-containing organosilicon compound (B) is 0.4-5. The surface of silica finer powder is hydrophobilized by alkyl group-containing silicon compound, vinyl group-containing silicon compound and 3C or more perfluoroalkyl group-containing silicon compound. The fluorine-containing repeating unit is of formula: -CaF2aO- (I).    a=1-6.