To provide a primer composition which, when used for coating a molded polyolefin resin article, exhibits an excellent adhesiveness to a polyolefin just only washed with water and which is excellent in resistance to high-pressure water washing.

This primer composition for a polyolefin resin comprises a specific carboxyl-group-containing chlorinated polyolefin, an acrylic-modified chlorinated polyolefin, an ethylene-vinyl acetate copolymer, and an alkyd resin.