To provide a polyolefin resin composition having a large strength and elongation, and having excellent adhesiveness to a coated film.

This resin composition comprises (A) 70-99.8 pts.wt. polyolefin resin, and (B) 30-0.2 pts.wt. graft polymer. The graft polymer (B) is obtained by reacting a raw material mixture comprising (1) 2-70 pts.wt. low molecular weight polyolefin, (2) 30-98 pts.wt. vinyl monomer and (3) 0.01-5 pts.wt. radical initiator at 150-300°C for 1-60 min.