PURPOSE: To launch an underwater sailing body from a long distance without being passively detected.

CONSTITUTION: When a self-ship 20 detects a target fleet by means of sonar installed to a mother ship 1, a guidance control device for the ship 20 connected with the sonar 2 by way of a relay and a communication cable 5 controls a propulsion device, a rudder, and an underwater rudder, and accurately guides the mother ship 1 at the target fleet 30. When the mother ship 1 arrive at the center of the target fleet 30, the guidance control device launches a plurality of underwater sailing bodies 3 from the mother ship 1 simultaneously and guides them to each of ships 30-1 to 30-4 of the target fleet 30 based on the detection result of the sonar of the mother ship 1. When each of underwater sailing bodies 3-1 to 3-4 approach the target ships 30-1 to 30-4 up to a distance that can be chased by a homing function, they try to chase, detecting the targets and hit the targets.