PURPOSE: To obtain a sonar detection information simultaneously at a plurality of positions over a wide region and at the same time a recovery type sonar device where its floating labeled body can be moved to an installation point.

CONSTITUTION: A title item is provided with a buoy 12 with a floating side transmitter 8 which outputs a detection signal and a sonar detection information for a flying body, etc., for detection and a receiver 14 for sonar which is suspended through a cable 13 at the buoy 12. Then, it is also provided with a controller 10 which is provided within the buoy 12 and transmits the detection information which is collected by the receiver 14 for sonar to a floating side transmitter 9 and is in an engagement structure which functions when the buoy 12 is recovered.