A steering system in a vehicle includes a plurality of subsystems provided with a control unit. The control unit includes a storage unit storing steer angle information regarding a steer angle of one of a steering mechanism and a steered mechanism when the steering mechanism or the steered mechanism stops, an abnormality determiner determining abnormality of the motor rotation detection value and the detection circuit in the plurality of subsystems at a start time of a motor based on a comparison of at least two parameters, and a steer angle calculator calculating the steer angle based on the parameters having been determined by the abnormality determiner as not abnormal.