A method including: a first step of preheating a rotor core body 12; a second step of attaching a cull plate 21 onto a surface of the body 12 removed from a preheating device 20; a third step of placing the body 12 in a resin-sealing mold 19; a fourth step of heating and liquefying resin 15 in resin reservoir pots 29 by the mold 19; a fifth step of extruding the liquefied resin 15 into plural magnet insertion holes 13 and curing the resin 15; and a sixth step of ejecting a laminated rotor core 10 from the mold 19 and detaching the plate 21, wherein the second step of attaching the plate 21 and the sixth step of detaching the plate 21 are performed at a same station 22, and the plate 21 detached at the sixth step is used as the plate 21 at the second step.