Abstract: A method of manufacturing a toothbrush comprises providing an integral head mold configured to simultaneously form bristles and head board in one injection molding process, heating head molding material to a predetermined temperature, filling the integral head mold with the head molding material in an injection molding machine, applying pressure to the integral head mold for a predetermined period and applying a cooling process to the integral head mold to produce a molded integral head. The molded integral head includes bristles molded on a head board.