PURPOSE: To facilitate the adjustment of the axis of a valve shaft for reducing the production cost for a device by securing multiple connection pipes integrally fixedly to each other on the fixing parts of a contact surface to insert a valve shaft only into a pair of bearings.

CONSTITUTION: Multiple connection pipes integrally made of a plurality of adjacent pipes by fixedly mating contact surface 14 with each other formed on adjacent contact parts of pipes 10, 11 constituting a resonator of a muffler are provided. Also, valves 12, 13 built in the pipes 10, 11 are integrally interconnected with a valve shaft 15 so that the valves 12, 13 constitute the multiple system valve. First and second bearings 16, 17 into which the valve shaft 15 is inserted are secured to bearing holes 20, 21. The valve shaft 15 is inserted only into two upper and lower bearings 16, 17 and will do only by loosely fitting in the shaft hole 19 between the pipes. Thus, the adjustment of the axis of the valve shaft is extremely facilitated and production cost of the device can be reduced.