To enable the miniaturization and cost lowering of an antenna device for tracking by detecting a deviation of the direction of the beam of the antenna relative to a specific direction and drive-controlling an orientation adjusting means so that the detected output may become zero.

A base table 22 is fixed on a mobile body 20. A rotation table 24 is provided over the table 22 and supported by a center rotation shaft vertically provided at the center of the table 22. The rim of the table 24 is provided with a driving wheel 26 which is driven by a motor 30 and the driven wheel 28, and the table 24 is driven to rotate. A flat antenna 32 and a gyro 50 whose rotation axis is arranged in parallel with the table 24 are provided over the table 24. A controller 38 controls the motor 30 on the basis of the signals and the level of reception from the gyro 50. As the integrating of the angular speed signals from the gyro 50 is proportional to the angle of deviation relative to an direction to a satellite, the motor 30 is driven to the direction that makes this integrated value zero. This method eliminates the need for arranging the gyroscope 50, etc., on the table 22, and therefore miniaturization becomes possible.