A shaped article of synthetic resins, such as polydiethylene glycol bisallylcarbonate, is coated with the following coating composition and then irradiated with ultraviolet rays, whereby the coating composition deposited on the shaped article is cured to form a coating film having an excellent abrasion resistance, surface smoothness, adhesion to the substrate resin, flexibility, heat resistance, solvent resistance and durability. The coating composition comprised of (a) a mixture of, based on the weight of the mixture, (i) 25-99.95 wt. % of at least one polyfunctional monomer having at least three acryloyloxy or methacryloyloxy groups, (ii) 0-50 wt. % of at least one mono- or bi-functional monomer having one or two polymerizable unsaturated groups and (iii) 0.05-25 wt. % of at least one organic acid which has at least one halogen substituent (fluorine, chlorine or bromine) and which is liquid at normal temperature and pressure, and (b) 0.01-10 wt. parts, based on 100 wt. parts of said mixture, of a photosensitizer. The coating composition may contain 0.05-25 wt. % of at least one compound having an acrylamide or methacrylamide group and a hydroxyl group or groups.