Abstract: An apparatus for rotating and driving an antenna device in a radio transmitter and receiver which can simply increase and decrease the driving torque by variation in weight thereof. This apparatus comprises a rotary body rotatably mounted on a main housing and supporting the antenna device thereabove, and one or more driving units detachably mounted on the main housing. The rotary body is connected to an input gear rotatably provided on the main housing through a gear mechanism. Each of driving units has a driving source and a keyway gear connected through the gear mechanism, the keyway gear being meshed with the input gear when the driving unit is mounted on the main housing. Thereby, the driving torque required for rotation of the antenna device is adjusted by increase or decrease in number of the driving units.