PROBLEM TO BE SOLVED: To provide a syringe outer cylinder which, even when a connected circuit, etc. have an inner pressure, prohibits the inner pressure from being transferred to within the syringe outer cylinder and obstructs backflow of a liquid in the circuit and transfer of the inner pressure in the circuit to a gasket, thus preventing leakage of the liquid from the circuit.SOLUTION: A syringe outer cylinder 1 comprises: an outer cylinder body 2 having a distal portion 22 with an opening 25； a nozzle member 4 secured to an exterior surface of the distal portion 22 of the outer cylinder body 2； and a check valve 6. The nozzle member 4 has an orifice 42 at its distal end to discharge liquid. The syringe outer cylinder 1 includes a flow channel 15 for communication between the opening 25 of the outer cylinder body 2 and the orifice 42 of the nozzle member 4, with the check valve 6 disposed within the flow channel 15. The check valve 6 permits the flow of liquid from the opening 2 side of the outer cylinder body 2 to the orifice 42 side of the nozzle member 4 and obstructs the flow of liquid from the orifice 42 side of the nozzle member 4 to the opening 25 side of the outer cylinder body 2.SELECTED DRAWING: Figure 5COPYRIGHT: (C)2020,JPO&INPIT【課題】接続された回路等が内圧を有するものであっても、その内圧がシリンジの外筒本体内に伝達されず、回路内の液体の逆流、回路内の内圧のガスケットへの付与を阻止し、回路内の液体の漏出を防止できるシリンジ用外筒を提供する。【解決手段】シリンジ用外筒１は、開口２５を有する先端部２２を備える外筒本体２と、外筒本体２の先端部２２の外面に固定されたノズル部材４と、逆止弁６とを備える。ノズル部材４は、先端に液体排出のための開口部４２を備える。シリンジ用外筒１は、外筒本体２の開口２５とノズル部材４の開口部４２を連通する流路１５を備え、逆止弁６は、流路１５内に配置されている。逆止弁６は、外筒本体２の開口２側からノズル部材４の開口部４２側への液体の流動を許容し、ノズル部材４の開口部４２側から外筒本体２の開口２５側への液体の流動を遮断するものとなっている。【選択図】図５
