To instantly generate high pressure air having few pressure fluctuation and high accuracy so as to use for pressurized high pressure without using a pressure control valve, and supply the air stably by arranging a plurality of air tanks and a plurality of pressure regulating valves in a secondary side air supplying path, and regulating pressure of air.

Pressurized air is supplied from a pressurized air supplying source 5 to a primary side cylinder 10 of a booster cylinder 9 through a primary side air supplying path 6 with a solenoid valve 7 and a throttle valve 8. A secondary side air supplying path 16 built in a check valve 15 for preventing reverse flow of air and which is divided from the primary side air supplying path is connected to a secondary side cylinder 11 of the booster cylinder 9. Furthermore, a pressure regulating path 17 having a plurality of air tanks is connected, and a pressurized port 19 is connected through a solenoid valve 18.