PURPOSE: To apply antenna direction control with small size, light weight and high accuracy by using a driver provided separately so as to direct the antenna not by changing the antenna direction through the control of the thrust motor.

CONSTITUTION: The turning of a motor 14a as a drive source is reduced to an optional speed and turning angle, and delivered to a worm 6a and a worm wheel 7a via a gear head 15a. Since the worm wheel 7a is turned around an output shaft 9, the torque is delivered to bevel gears 5, 20 via a bevel gear 23a. The bevel gears 5, 20 are turned around the shaft 8 and also around the output shaft 9. The torque from the motor 14a is delivered to flanges 12, 39 to change the angle of the antenna.