In a hybrid power steering system, two steering assisters for supporting a steering force when the driver operates the steering wheel. The steering supporting force can be divisionally used according to the increase of speed and weight of a vehicle, thereby reducing the load applied to any of the steering assisters such that operating noise can be reduced and the endurance can be increased. Further, a motor of a lower power specification may be used even in the case of a truck or a bus that requires a relatively high steering force as compared to a passenger vehicle. Accordingly, production costs can be reduced and a sufficient steering supporting force can be obtained, thereby improving the driver's convenience, and enhancing fuel efficiency while increasing energy efficiency. Further, the steering can be safely maintained even when one of the steering assisters is not operating normally while the vehicle is being driven.