To lower a radial force acting on a valve shaft so as to improve reliability and durability by providing a full opening stopper near a wire drawing-out position.

A throttle body 1 is provided with a valve shaft 5 turnably, while the valve shaft 5 is provided with a valve element 7 opening/closing a throttle chamber 2 and a wire drum 8 winding a wire. When a wire is drawn out from the wire drum 8 so that the valve shaft 5 is turned largely, an abutting part 12 toward the valve shaft 5 abuts on a full opening stopper near a wire drawing-out position. Accordingly a force acting on the valve shaft 5 in a valve opening direction through the wire is counteracted by a reactive force acting on the valve shaft 5 caused by the full opening stopper.