Abstract: A valve of a vacuum apparatus with a valve seat body having left and right communicating openings opposed to the two vacuum chambers, respectively, a valve body movable in the axial direction of the valve seat body and rotatable around the center axis thereof, and a driving section for moving the valve body in the axial direction of the valve seat body and for rotating it around the center axis thereof, the valve being so disposed between the left and right vacuum chambers that the driving section of the valve is projected outwardly in the horizontal (lateral) direction.