PURPOSE: To provide the subject novel composition having a specific composition, excellent in the balance between the rubber elasticity and mechanical strength thereof, excellent in the mechanical strength such as tensile strength and the rubbery physical properties such as heat resistance, oil resistance and elongation set, and advantageous from the production cost.

CONSTITUTION: The objective composition comprises (A) the resin mixture of (i) a polypropylene resin and (ii) a polypropylene resin grafted compound produced by graft-polymerizing at least one of glycidyl, amino, COOH, acid anhydride and OH group-containing monomers onto (ii) a polypropylene resin, (B) an ethylenic copolymer comprising ethylene and 1-30wt.% of a carboxyl group-containing polymerizable compound and/or 0.5-7wt.% of an acid anhydride- containing polymerizable compound, (C) an ethylenic copolymer comprising ethylene and 2-30wt.% of a glycidyl group-containing polymer compound and/or a hydroxyl group-containing polymer, and (D) a reaction accelerator for the components B and C, the content of component A being 10-65wt.% the total amount of the components B and C being 90-35wt.%, an the ratio of the function groups of the components B and C being 0.02-20.