PURPOSE: To make the functions of both systems of a radio wave and a light wave compatible, by using an antenna for a radio wave and an optical system for a light wave in common and providing a frequency selection board for separating a radio wave and a light wave to arrange a primary emitter for a radio wave and a detector for a light wave in a separated state.

CONSTITUTION: The radio wave signal such as the radar signal generated from a transmitter 6 is sent to a primary emitter 4 by a duplexer 5 and reflected by a frequency selection board 13 to be emitted to a space from an antenna constituted of a main reflective mirror 1 and an auxiliary reflective mirror 2. Contrarily, the reflected signal from a target passes a route reverse to that at the time of transmission to be sent to a receiver 7 by the duplexer 5 and the detection of a target signal is performed by a signal processor 8. The light wave such as infrared rays emitted from the target uses the radio wave anttenna constituted of the main reflective mirror 1 and the auxiliary reflective mirror 2 as a reflective optical system in common and transmits the frequency selection board 3 to be converted to an electric signal by a detector 9. By this method, because the wave form primary emitter 4 and the light wave detector 9 can be arranged in a separated state, both systems of a radio wave and a light wave can be made compatible without lowering the functions thereof.