PURPOSE: To provide a thin linear motor, which operates stably, by so arranging racks, which are provided in a stator and a rotor, respectively, that they sandwich a gear.

CONSTITUTION: A first rack 2 is provided in a stator 2, and a second rack 3 is provided in a needle 8. A retainer 6, which retains a roller 7 between the stator 5 and the needle 8, bears the shaft of a gear 1 rotatably. The first rack 2 and the second rack 3 are provided in opposition, and the gear 1 is provided between them to engage with both sides. The stator 2, the needle 8, and the roller 7 shift along guide rails with the positional relation being maintained properly by the first rack 2, the second rack 3, and the gear 1. Moreover, by providing the stator 5 with a sidewall 4 in opposition to the rack 2, the engagement between the needle 8, the rack 3, and the gear 1 can be prevented more surely from coming out.