An injection molding device includes: a lower die that supports a rotor core; an intermediate die including a magnetizing mechanism; and an upper die including an injection die having a gate formed therein through which a molten bonded-magnet material supplied from a supply source is injected into a magnet insertion hole in the rotor core. The injection die has a cylindrical protruding portion at an end surface of which the gate is open. In the protruding portion, a magnetic-flux applying member containing ferromagnetic material is embedded with its side surface exposed at an outer peripheral surface of the protruding portion. The magnetizing mechanism is formed in an annular shape that can accommodate, inside its inner periphery, the rotor core and a distal end portion of the protruding portion by disposing yokes and permanent magnets alternately in the circumferential direction. Magnetic-path surfaces of the yokes radially face the side surface.