PURPOSE: To provide the subject profitable composition comprising ethylene- acrylic ester copolymer rubber and specific silica in a specified amount based on the rubber, and capable of realizing an ordinary temperature vulcanization.

CONSTITUTION: The composition comprises 100 pts.wt. of an ethylene-acrylic ester copolymer rubber, the random copolymer of ethylene with an alkyl acrylate, 1-20 pts.wt. of silica (preferably synthetic silicic acid) having an oil absorption of ≥200ml/100g and, if necessary, a filler, a plasticizer, etc.