PURPOSE: To miniaturize and lighten a steering device for a flying object and to enhance the reliability of the device by providing a first lock gear to the rotary shaft of a steering servo motor, and providing a second lock gear on the side of an airframe in such a manner as meshing with the first lock gear and being axially supported after small rotation by a guide shaft which is movable in the direction of the axis of the second lock gear.

CONSTITUTION: A first lock gear 5 is mounted on the output shaft 3 of a servo motor 6 and a locking mechanism portion 18 is provided at the center of the motor in such a manner as meshing with the gear 5. The locking mechanism portion 18 comprises a lock gear 8, a brake mechanism portion 19 which stops rotation of the lock gear 8 until predetermined driving torque is delivered, a spring 20, a stopper pin 21, and a guide shaft 22 which axially supports the lock gear 8 in such a manner as allowing the gear 8 to freely slide thereon. When transfer torque is increased more than the braking torque of the brake mechanism portion 19 by rotation of the steering angle servo motor 6, the lock gear 8 starts to rotate and, when the stopper pin 21 is engaged in a notch hole 25, moves in the direction of its axis to release the lock gear 5.