PURPOSE: To obtain FRP products having surface with a certain fixed gloss at all times by a method wherein a parting agent is prepared at a certain fixed property.
CONSTITUTION: Firstly, a gelcoat layer 3 is formed onto the surface of an FRP mold 1. Secondly, parting agent prepared by dispersin matting agent in aqueous solution of polyvinyl alcohol or the like is coated onto the surface of the FRP mold 1 in order to form a parting film 4 by drying. Thirdly, polyester resin or the like is coated onto the parting film 4 in order to form a gelcoat layer 5. Fourthly, glass matted cloth 6 is placed onto the cured gelcoat layer 6. Fifthly, liquid thermosetting resin such as polyester resin or the like is coated onto the cloth 6. Sixthly, the above-mentioned layers, film, and cloth as a whole are deaired-impregnated by means of rolls and then cured in order to obtain an FRP product by taking off the mold 1. Desired fine irregularties can be formed on the surface of the parting film 4 by selecting powder size of parting agent, blending ratio of polyvinyl alcohol aqueous solution and matting agent, kind of parting agent and the like. Accordingly, an FRP product having the surface with a desired gloss, which is ranged widely, can be obtained by reversing said fine irregularities onto the FRP product.