PURPOSE: To aim quickly and correctly, by a method wherein aiming data are operated automatically by inputting the measured initial velocities of respective guns on-line and making a correction in accordance with the deviation of the initial velocity to the elevation of a reference gun without depending on the trajectory operation of the elevations of guns except the reference gun.

CONSTITUTION: The initial velocities of respective guns 1W3 are measured by initial velocity measuring devices 4W6 to input them into an initial velocity difference operating device 13 through initial velocity transmitting devices 7W9 and initial velocity receiving devices 10W12 while the initial velocity of a reference gun and the deviations of initial velocities of respective guns are operated in the device 13 and the operated data are stored into an initial velocity deviation memory 14. An aiming data operating device 15 inputs the initial velocity of the reference gun to obtain an elevation by trafectory operation and, further, operates the elevations of guns except the reference gun from the deviation of initial velocities of respective guns 1W3, range correction coefficient per unit time of the initial velocity and an elevation correction coefficient to transmit them to respective guns 1W3 through the transmitting devices 16W18. The guns may effect aiming quickly and correctly in such a manner.