PURPOSE: To prevent kick back by operating a braking means to regulate steering shaft rotation when more than prescribed reverse input force is detected by an external force detecting means.

CONSTITUTION: When steering angle speed H and reverse input torque Tm obtained from detected signals of a steering angle sensor 2 and a torque sensor 3 which are an external detecting means 7 exceed a prescribed value, it is judged that more than prescribed external force has been inputted to a wheel 8. Besides, a braking means (electromagnetic brake) 12 is operated by a braking means (brake circuit) 11 provided in a power steering circuit 5, rotation of a steering shaft is regulated to carry out braking control which prevents kick back. It is thus possible to prevent kick back with high efficiency.