To eliminate the operation delay of a pneumatic piston caused by a pneumatic booster device to pressurize air.

A bypass with a pneumatic booster device 11, a bypass with a check valve 12, and a bypass with an exhaust valve 13 are connected to a port 9 on the side of a head cover 7 of a pneumatic cylinder 1 to form parallel flow passages. The port 9 on the side of the head cover 7 is connected to a switch valve 10 through these three bypasses. The exhaust valve 13 is switched by an pneumatic pressure supplied to a port 8 on the side of a rod cover of the pneumatic cylinder 1 as a pilot pressure.