Abstract: The present invention provides a set of split bodies for forming a synthetic-resin blower fan through a hollow-article injection molding process, wherein the blower fan integrally includes a circular base, a doughnut-shaped cover portion having an air inlet opening at the center thereof, and a plurality of blades each extending radially between the circular base and the inner surface of the cover portion to define a plurality of radial airflow passages between the adjacent blades. The set of split bodies comprises a first split body including the circular base and a plurality of blade members, and a second split body defining the inner surface of the cover portion and having an outer surface on the opposite side of the first split body.