A rotor manufacturing apparatus configured to manufacture a rotor including a magnet and a rotor body in a cylindrical shape having an accommodating hole for accommodating the magnet, the magnet being fixed with resin in the accommodating hole, the rotor manufacturing apparatus comprising: a first mold provided with a resin pot having opposite ends with respective opening portions (5a, 5b); a plunger that is located in the resin pot and is movable from one of the opening portions (5a, 5b) of the resin pot toward the other; and a second mold on which the rotor body is mounted and that is located facing the first mold, the first mold including a first mold body having the resin pot, a runner plate in a tabular shape located between the first mold body and the second mold while being allowed to separate from the first mold body in a thickness direction, the runner plate having a recess located on a side in contact with the first mold body, the recess constituting a part of a flow path for allowing the resin melted to flow, and a resin accommodating space surrounded by the resin pot, the plunger, and the recess to accommodate melted resin in a state where the first mold body and the runner plate are in contact with each other, the flow path communicating with the resin accommodating space in a state where the first mold body and the runner plate are in contact with each other, characterised by that the resin pot has a portion in a shape of a groove in the circumferential direction on the outer peripheral surface of the resin pot that allows melted resin to flow and solidify around the portion. a first mold provided with a resin pot having opposite ends with respective opening portions (5a, 5b); a plunger that is located in the resin pot and is movable from one of the opening portions (5a, 5b) of the resin pot toward the other; and a second mold on which the rotor body is mounted and that is located facing the first mold, the first mold including a first mold body having the resin pot, a runner plate in a tabular shape located between the first mold body and the second mold while being allowed to separate from the first mold body in a thickness direction, the runner plate having a recess located on a side in contact with the first mold body, the recess constituting a part of a flow path for allowing the resin melted to flow, and a first mold body having the resin pot, a runner plate in a tabular shape located between the first mold body and the second mold while being allowed to separate from the first mold body in a thickness direction, the runner plate having a recess located on a side in contact with the first mold body, the recess constituting a part of a flow path for allowing the resin melted to flow, and a resin accommodating space surrounded by the resin pot, the plunger, and the recess to accommodate melted resin in a state where the first mold body and the runner plate are in contact with each other, the flow path communicating with the resin accommodating space in a state where the first mold body and the runner plate are in contact with each other, characterised by that the resin pot has a portion in a shape of a groove in the circumferential direction on the outer peripheral surface of the resin pot that allows melted resin to flow and solidify around the portion.