Abstract: A motor-driven lock (2) includes a housing (3), a lock body (4), a motor (5), a transmission device (6) mating with the motor and the lock body, a lid (7), an enclosure (8), and a cover (9). The lock body includes a controller (41) having a gear portion (410), and a cap (43) attached to the controller. The transmission device includes a first gearshaft (60) mating with the motor, a second shaft (61) meshed with the first gearshaft, a wheel (62) meshed with the second gear shaft, a screw shaft (63) fixing the wheel thereon, a slider (64) mating with the screw shaft, a yoke (65) slidingly movable along the housing and actuatable by the slider, and a gear set (66) attached to the cap of the lock body, meshed with the gear portion of the lock body and mated with either of two racks (653) of yoke.