PURPOSE: To suppress the generation of a black smoke in exhaust gas during the operation releasing period of an exhaust brake device.

CONSTITUTION: An opening/closing valve 42 or a cut valve which prohibits outflow of compressed air in an actuator 18 as well as to be closed when an exhaust brake valve 12 is closed so that the supply of the compressed air from a compressed air source 30 to the actuator 18 is cut off, is interposed between the pressure response type actuator 18 which controls opening/closing the exhaust brake valve 12 and a three-way solenoid valve which is energized during the engine brake traveling period of a vehicle so that the compressed air in the compressed air source 30 is supplied to the actuator 18.