To obtain the subject composition comprising a specific epoxy compound, a resin, a photopolymerization initiator, and a pigment, excellent in photocurability in spite of containing the pigment, capable of forming coating films excellent in adhesivity, processability and surface hardness, and useful for coating materials for surface-treated steel plates, etc., and for inks, etc.

This UV light-curable resin composition comprises (A) an epoxy compound liquid at the ordinary temperature [e.g. the mixture of (A1) an aliphatic epoxy compound liquid at the ordinary temperature with (A2) another epoxy compound except the component A1, such as a glycidyl ether epoxy compound solid at the ordinary temperature or a novolak epoxy compound solid at the ordinary temperature wherein the component A1 is contained in an amount of ≥50wt.%], (B) a resin such as a petroleum resin (e.g. a diolefin resin, a 5C petroleum resin, a 9C petroleum resin, a ketone-formaldehyde resin, a xylylene-formaldehyde resin), a terpene resin and a rosin resin), (C) a cation photopholymerization initiator having a light-absorbing area (a wavelength range of 350-450nm) of ≥10% in the whole light-absorbing area (a wavelength range of 200-500nm) (e.g. a diaryliodonium hexafluoroantimonate), and (D) a pigment.