A torque sensor and an electric motor are supported by a steering column by which a steering shaft is rotatably supported. On a control board on which a control circuit that controls driving of an electric motor is mounted, a first terminal group and a second terminal group that are selectively connected to the torque sensor are respectively provided at a first end portion and a second end portion in a first direction parallel to a central axis of the steering shaft. A third terminal group that is connectable to the electric motor is provided at one end portion (third end portion) in a second direction perpendicular to the first direction.