To provide a driving gear which is small in size and low in cost and high in output, and can be driven stably.

The driving gear has a coil which is concentric with a magnet 1 and arranged in the axial direction of the magnet, a stator 4 of which tooth-like outside magnetic poles 4a and 4b face the outer peripheral surface of the magnet and excited by the coil, and a rotor 5 of a soft magnetic material of which one end side in axial direction is inserted in the inner diameter part of the coil, and the other end side is fixed to the inner diameter part of the magnet, being excited by the coil. The profile vertical to the axial direction of the other end side of the rotor has the shape where protruding parts 5d and 5e are large in outer diameter dimension while recessed parts 5f and 5g are small, in circumferential direction. The protruding parts are so fixed to the inner diameter part of the magnet as to face the outside magnetic pole, being used as the inside magnetic pole.

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