To provide an inexpensive non-chlorine-type graft-modified polyolefin having improved adhesion to polyolefins and melt moldability.

The graft-modified polyolefin composition contains (A) a graft copolymer of an unsaturation-terminated polypropylene-based polymer and a 1,2-disubstituted ethylene type monomer or a graft copolymer of the unsaturation-terminated polypropylene-based polymer, the 1,2-disubstituted ethylene type monomer, and a radically copolymerizable monomer therewith, and (B) a graft copolymer of an ethylene-vinyl acetate-based copolymer and a 1,2-disubstituted ethylene type monomer or a graft copolymer of the ethylene-vinyl acetate-based copolymer, the 1,2-disubstituted ethylene type monomer, and a radically copolymerizable monomer therewith. The graft-modified polyolefin composition has composition of: 75-10 wt.% of the unsaturation-terminated polypropylene-based polymer; 5-40 wt.% of the ethylene-vinyl acetate-based copolymer, and 20-50 wt.% of the 1,2-disubstituted ethylene type monomer polymerization residue or the 1,2-disubstituted ethylene type monomer polymerization residue and the radically copolymerizable monomer polymerization residue therewith, wherein the total is 100 wt.%.