PURPOSE: To prevent unintentional change in the course of a car due to the braking torque difference between the left ad right wheels by sensing the braking torque difference, and controlling the aid steering angle so as to offset the yaw moment originating from the braking torque difference.

CONSTITUTION: A car A is equipped with a device B for aid steering of either or both of the front and rear wheels independently from main steering on the front wheels. The braking torque difference between the left and right wheels is sensed by a means C. The aid steering device B is controlled by a means D so as to offset the yaw moment originating from the braking torque difference thus sensed. At this time, control is so made as to decrease the amount of the aid steering angle in the region where the amount of main steering is large. This prevents unintentional change in the course of the car A due to the braking torque difference, which should eliminate giving an anxious sense to the driver.