A wing driving apparatus is made up of a flight controller part for
generating a drive signal, first and second servo actuators, a first
controller unit having a first drive circuit, and a second controller
unit having a second drive circuit. The first controller unit includes a
follower signal generator circuit for generating a follower signal. The
second servo actuator includes a solenoid valve for invalidating a
control to the second serve actuator based on the drive signal from the
second drive circuit in response to the follower signal, whereby the
second second servo actuator follows the steering wing when the first
drive circuit is able to operate the first servo actuator to drive the
steering wing.