Medical suction device, negative pressure forming device, and plug member having one-way valve

摘要

PROBLEM TO BE SOLVED: To provide: a negative pressure forming device capable of preventing unexpected splash of waste water by preventing the waste water from jetting toward the opening of an outlet port when the waste water is sucked and discharged; a plug member having a unidirectional valve for the negative pressure forming device; and a medical suction instrument.SOLUTION: The medical suction instrument 100 includes: a negative pressure forming section 10 for forming a negative pressure by discharge of air; and a reserving container 50 for reserving the waste water sucked by the negative pressure. The negative pressure forming section 10 includes: a pump section 11 for discharging the air from the outlet port 12 by contraction; a suction container 13 for forming the force of sucking the waste water by a negative pressure in its inside by the discharge of air; a unidirectional valve 20 disposed on the outlet port 12, permitting the discharge of air and preventing the aspiration of air inlet; and a returning member 30 disposed facing the outlet port 12 and allowing the air and the waste water to abut thereon.