PURPOSE: To display a warning of driving of an actuator to a user or peripheral persons at the time of starting the rotation driving of an antenna by this actuator for a rotating satellite antenna which automatically tracks BS and CS based on user's satellite designating operation to receive the transmission radio waves.

CONSTITUTION: A new pulse (c) is generated in a second pulse generating part 3 based on a pulse (a) from a first pulse generating part 10 provided in an actuator 9. This new pulse has the frequency divided into pulses which have a period adapted to flickering by a frequency divider 4. These divided pulses are amplified to prescribed phase and level by a warning light drive circuit 6 to flicker the indicator of a warning display part 7. Meanwhile, the pulse from a second pulse generating part 3 is monitored by a pulse detecting part 5; and when the output of the pulse (c) is stopped by the stop of antenna driving, the output of the frequency divider 4 is stopped to stop flickering of the indicator.