PURPOSE: To obtain a high aiming probability for a target behind a master aircraft by providing separating means for separating additional wings in the air, and air speed sensing means for sensing, when the speed of a missile launched rearward from the aircraft reaches near '0', it and operating the separating means.

CONSTITUTION: Additional wings 4, in which the position of aerodynamic center to the center 10 of gravity is inverted, are detachably mounted at the rear of steering wings 3 of a missile 1 by blasting bolts 9. A differential pressure sensor 5 is provided and so composed that the aerodynamic center is disposed at the front from the center 10 of gravity with respect to the missile 1 until the missile 1 launched rearward of a master aircraft is separated from an inertial speed given by the aircraft by its own propulsion unit. The bolts 9 are blasted by a signal of the sensor 5 sensing, about when the air speed becomes '0' due to cancelling of the inertial speed by the own propulsion speed, it thereby to separate the wings 4 to move the aerodynamic center rearward from the center 10 of gravity, and hence the missile 1 obtains a stable aerodynamic force to obtain high aiming probability to a target.