PURPOSE: To enable an accurate guiding control of an underwater navigating body by a method wherein the underwater navigating body is provided with a means of communicating with a mother ship by using an ultrasonic wave, and the motor ship, obtaining underwater navigating body information and target information from the underwater navigating body, executes computation of an optimum course of the underwater navigating body accurately and transmits control information to the underwater navigating body.

CONSTITUTION: An underwater navigating body 23 is equipped with a transmitter-receiver 29 for communication in addition to a transmitter-receiver 28 for homing. Based on information on relative positions of a mother ship 22 and the underwater navigating body 23, the transmitter-receiver 29 for communication conducts generation 27 of an adapted beam for communication, and thereby guiding to a target 24 is conducted while underwater body information and target information 25 and underwater navigating body control information 26 are interchanged every moment between the mother ship 22 and the underwater navigating body 23. The frequency of an ultrasonic waver used for the communication between the mother ship and the underwater navigating body, the frequency of the ultrasonic wave transmitted by the underwater navigating body for homing and the frequency of the ultrasonic wave transmitted by a sonar apparatus of the mother ship are made different from one another. Since a large-scale computer can be applied to an information processing apparatus equipped in the mother ship, besides, high-grade computation, including complicated underwater acoustic wave propagation characteristics, which has been impossible to execute heretofore can be executed, and thus computation of an optimum course can be conducted accurately.