A laminated rotor core (36) wherein permanent magnets (47) are inserted in respective magnet insertion holes (46) is disposed between and pressed by an upper die (37) and a lower die (29). The upper die (37) has resin reservoir pots (50) provided above the laminated rotor core (36) and at positions corresponding to the respective magnet insertion holes (46). Raw resin material put in the resin reservoir pots (50) is heated by the upper die (37). Subsequently, the resin material in a liquefied state is ejected from the resin reservoir pots (50) by plungers (52) that are inserted and moves vertically in the resin reservoir pots (50) and is directly filled in the magnet insertion holes (46). Consequently, the respective magnet insertion holes (46) are filled with the resin material more evenly and highly reliable products can be supplied at low cost.