Provided is an aqueous resin composition in which a vinyl ester resin and a urethane resin having an aromatic ring are dispersed in an aqueous medium, in which the vinyl ester resin is obtained by allowing at least one epoxy resin selected from the group consisting of a novolak type epoxy resin and a bisphenol type epoxy resin to react with a compound having an acid group and a polymerizable unsaturated group, and the urethane resin is obtained by allowing polyol containing polyol having an aromatic ring and polyol having a hydrophilic group to react with a polyisocyanate. A primer using the aqueous resin composition is able to considerably improve adhesiveness between a substrate and a cured coating film of an active energy ray curable composition, even when the substrate is a sparingly adhesive substrate.