A fluid sucking and discharging device wherein a piston (2) moves to produce a depressurized state and a pressurized state in a cylinder (1) to suck a fluid and discharge the fluid, characterized in that the piston has a plurality of sealing portions (3,6) which contact with an inner surface of the cylinder, the sealing portions being arranged so as to be layered, the sealing portions has a gap (8) formed between opposed sides thereof; and the gap has at least one of a liquid and a lubricative viscous material sealed therein. IMAGE
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