To provide a small light-weight motor capable of smoothly adjusting to the drive of both high speed and high torque without trouble.

A load sensitive motor automatically changes a transmission gear ratio of a transmission mechanism while maintaining a rotation speed of the motor 3 constant. A planetary rotating body 8 having a plurality of planetary members 18 is provided. The transmission gear ratio is changed when the planetary members 18 tilt. The planetary member 18 is supported at three points by a rotor 6, a rotation output body 7, and a pressing body 11, and tilts when a moving body 10 slidingly displaces. The moving body 10 rotates and displaces in synchronization with the pressing body 11. When the rotation output body 7 receives a load from an external, the pressing body 11 rotates and displaces, and in accordance with it, the moving body 10 rotates and displaces. When the moving body 10 rotates and displaces, a pressure pin 23 relatively displaces in a recessed part 10e and the moving body 10 slidingly displaces.