Abstract: A control valve driving device wherein a control valve is provided in an intake or an exhaust system of an internal combustion engine and means for driving this control valve in response to an operating condition of said internal combustion engine is provided. An opening angle of the control valve is operable to be changed to permit an intake or an exhaust characteristic to be changed. The control valve driving device is characterized in that the control valve can be driven only when a pressure in an intake or an exhaust pipe is at an acceptably low level.