The present invention relates to a primer coating composition including an aqueous polyolefin-based resin (A), an aqueous epoxy resin (B), a hydrophilicized-modified carbodiimide compound (C), and an aqueous polyurethane resin (D), in which the aqueous polyolefin-based resin (A) includes an aqueous polypropylene-based resin having a weight-average molecular weight of 50,000 to 200,000, and the hydrophilicized-modified carbodiimide compound (C) is a hydrophilicized-modified carbodiimide compound (C) having a prescribed structure.