PROBLEM TO BE SOLVED: To provide a prefilled syringe capable of preventing a leakage of liquid caused by an impact when the plunger is attached to a gasket and the leakage of liquid caused by the deformation of a surface of the gasket by an impact on a plunger in use during manufacturing processes, without requiring a rotation in attaching the plunger to the gasket.SOLUTION: The gasket 3 of the prefilled syringe 1 is composed of a gasket body 6 and a plunger attaching member 7. The gasket body includes an anti-loosening rib 62 for the plunger attaching member on the inner surface. The plunger attaching member includes: a body 70, head parts 73 and 74, and elastically deformable parts 75 and 76 which connect the head parts 73 and 74 to the cylindrical body 70. The head parts include side projections 73a and 74a to be engaged with the anti-loosening rib 62, and anti-loosening locking parts 73b and 74b for the plunger respectively. The plunger 4 is disposed on the outer surface of a cylindrical distal end 42, and has an outer surface projection 43 to be engaged with the anti-loosening locking parts.COPYRIGHT: (C)2012,JPO&INPIT【課題】ガスケットへのプランジャ装着時に回転の必要がなく、製造工程中での、ガスケットへのプランジャ装着時の衝撃による液漏れ、使用時のプランジャへの衝撃によるガスケット表面変形に起因する液漏れを防止できるプレフィルドシリンジを提供する。【解決手段】プレフィルドシリンジ1のガスケット3は、ガスケット本体6とプランジャ装着用部材7とからなり、ガスケット本体は、内面にプランジャ装着用部材抜け止め用リブ62を備え、プランジャ装着用部材は、本体部70と、ヘッド部73、74と、ヘッド部を筒状本体部70に連結する弾性変形可能部75,76を備え、ヘッド部は、抜け止め用リブ62と係合する側部突出部73a,74aと、プランジャ抜止用係止部73b,74bとを備える。プランジャ4は、筒状先端部42の外面に設けられ、抜止用係止部と係合する外面突起部43を備えている。【選択図】図16
