A rotor rotating apparatus includes: a first rotor that rotates; a second rotor supported rotatably at the first rotor and so as to revolve around an axis of the first rotor with rotation of the first rotor; a drive unit for rotating the second rotor; a transmission member configured to move along a direction of a rotation axis of the second rotor between a transmission position at which the transmission member transmits the drive force from the drive unit to the second rotor and a non-transmission position at which the transmission member idles: and a guide member that moves the transmission member to the transmission position when the first rotor is in a first rotation position, and moves the transmission member to the non-transmission position by rotation of the first rotor from the first rotation position.