To provide a compact driving force switching device capable of switching a driving force of a drive source in a short path to switch and transmit the driving force into a plurality of driven systems.

This driving force switching device is provided with a motor 15 rotatable forward and backward, a sun gear 33 rotating by a driving force of the motor 15, a planetary gear 34 meshing with the sun gear 33 to move on a revolution orbit, a carrier 35 supporting the planetary gear 34 on the revolution orbit, a cam part 35a connecting a plurality of cam grooves provided in the carrier 35, a locking lever 36 engaged with the cam part 35a to regulate the rotation of the carrier 35 at an end part position of the cam groove, a first zoom gear 41 arranged on the revolution orbit of the planetary gear 34 meshable with it, a first winding-up gear 51, a first winding-back gear 61, a carrier switch 26a detecting a position of the carrier 35, and a CPU controlling the rotation of the motor 15 by referring to the detection result.