To provide a suction and delivery device for fluid capable of substantially preventing the fluid from leaking even at a high-pressure, and a piston used for the device.

This suction and delivery device comprises a piston body reciprocatingly moving in a cylinder, holes for delivering the fluid formed in cylinder chambers formed separating the piston body, passages capable of sucking the fluid into the piston and feeding the fluid into the cylinder chambers, and check valves opening and closing the passages communicating with the cylinder chambers. When the fluid is delivered from one of the cylinder chambers, the passage in the piston allowed to communicate with the cylinder chambers is closed by one check valve by a delivery pressure, and the other cylinder chamber opens the other check valve in the piston with a sucking force to suck the fluid in communication with the passage in the piston.

COPYRIGHT: (C)2004,JPO