Abstract: A vulcanizable rubber composition composed of 100 parts by weight of a terpolymer rubber (A) composed of 35 to 80 mole % of epichlorohydrin, 15 to 50 mole % of ethylene oxide and 5 to 15 mole % of an unsaturated epoxide, 0.2 to 10 parts by weight of a non-sulfur vulcanizing agent, and 0 to 10 parts by weight of a vulcanization aid. A vulcanized rubber prepared from this composition has superior sour gasoline resistance (softening resistance and resistance to embrittlement) and cold resistance. A rubber mixture (B) of an epichlorohydrin-ethylene oxide copolymer rubber and an epichlorohydrin-unsaturated epoxide copolymer rubber containing 35 to 80 mole % of epichlorohydrin, 15 to 50 mole % of ethylene oxide and 5 to 15 mole % of an unsaturated epoxide may be substituted for the terpolymer rubber (A).