Provided are a resin material that is superior in coating appearance and adhesion to substrates and can be used not only under organic solvent-diluted conditions but also under aqueous solvent-diluted conditions; an undercoat agent for an inorganic-material thin film containing the same; and a molded body produced by using the undercoat agent for an inorganic-material thin film. Provided are a (meth)acryloyl group-containing acrylic-modified alkyd resin, an active-energy-ray-curable resin composition containing the same, the undercoat agent for an inorganic-material thin film, and a molded body produced by using the undercoat agent for an inorganic-material thin film.