To provide a method for manufacturing an FRP molded article, having a boss or rib on the outside of the bottom part thereof, of which the poor appearance caused by the generation of a pinhole or cavity is improved.

In a method for manufacturing an FRP molded article (bathtub) 20 having bosses or ribs 21 formed on the bottom part thereof and preferably having a stepped part formed on the side surface thereof by charging a fiber reinforced unsaturated polyester resin molding material in a mold 10 consisting of upper and lower molds 11, 12 to mold the same under heating and pressure, as the fiber reinforced unsaturated polyester resin molding material, a fiber reinforced unsaturated polyester resin molding material 20a containing calcium stearate along with zinc stearate being an internal release agent is used. A stepped part (armrest part) 22 is formed to the side surface of the FRP molded article (bathtub) 20.