To maintain operating safety by driving force distribution control system when an abnormal state arises and to smoothly transition from a normal state to an abnormal state without sudden changes in vehicle behavior. The driving force distribution control part calculates the transfer torque for the transfer clutch for the center differential device and the torque movement for the hydraulic motor for the rear wheel final reduction gear. When the control state detection part detects an abnormal state, there is control of the hydraulic motor in the direction that torque movement is lost on the one hand, and the transfer torque for the transfer clutch is controlled in the direction of front and rear distribution; after a preset time and after this control is carried out, the transfer torque drops.