In a steer-by-wire system 10, a first steering reaction force made-up value (Hc1) is determined in dependence on a road reaction force (W), and a second steering reaction force made-up value (Hc2) is determined in dependence on a steering position (X) of a steering handle 11 or steerable wheels 50. A steering reaction force command value (H) is generated from both of the first steering reaction force made-up value (Hc1) and the second steering reaction force made-up value (Hc2) the weightings on which are adjusted by respective weighting gains (G1, G2), and the ratio of the weighting gains is properly altered in dependence on the state of a road surface. Thus, it can be realized to provide the steer-by-wire system 10 capable of adjusting the steering reaction force to be sensitive or insensitive to the state of the road surface.