PURPOSE: To embed the pinholes and flaws on the surface of a lens made of molded plastic so as to easily prevent light scattering by providing cured layers consisting of a UV curing resin having the same refractive index as the refractive index of said lens onto the surfaces of the lens.

CONSTITUTION: A film forming concave mold 31 and a film forming convex mold 32 are combined and positioned apart at a prescribed spacing from each other by holding frames 33a, 33b on the front and rear faces of the optical lens 1 made of the molded plastic. A liquid UV curing resin material 37 having the same refractive index as the refractive index of the lens is then poured into spacing parts 35, 36 through a resin material supply port 34 provided to the frame 33a. UV rays are projected to said material through the film forming molds 31, 32 to cure the material. The molds 31, 32 are then removed and the material is further cured by secondary exposing, by which cured layers 21 are obtd. The pinholes and flaws on the lens surface are thereby embedded and the light scattering on the lens surface is easily prevented.