PURPOSE: To mass-produce a resin molded product having a flow pattern of sameness by a method wherein a plurality of nozzles respectively discharging pigments before a raw material is cured are allowed to face to the interior of the raw material and moved in the longitudinal direction of a mold while the pigments are discharged from the nozzles to certainly form the flow pattern to the surface of the resin molded product.

CONSTITUTION: The nozzle support member 4 arranged over the range from one end of a mold 2 for molding a resin molded product to the other end thereof and made movable in the longitudinal direction of the mold 2 and a plurality of the nozzles 3 supported by the nozzle support member 4 and positioned in the vicinity of the surface of the mold at the tips thereof are provided. Next, the raw material of the resin molded product is charged in the mold and a plurality of the nozzles 3 respectively discharging pigments before the raw material is cured are allowed to face to the interior of the raw material and moved in the longitudinal direction of the mold 2 while the pigments are discharged from the nozzles 3. By this constitution, the resin molded product having a flow pattern certainly formed thereto can be produced.