PROBLEM TO BE SOLVED: To provide a gasket for a syringe in which sealability between an outer cylinder and the gasket is improved so that a medicinal solution may not leak out from the syringe.SOLUTION: A gasket 3 for a syringe has a body 4 made of a rubber material, and a resin film 5 coated on a region 31 coming into contact with an inner circumferential surface 25 of at least an outer cylinder 2 of the body 4 and having a superior slidability. The gasket forms at least one sealing surface 35 coming into contact with an inner circumferential surface 25 of the outer cylinder 2. The sealing surface 35 is configured by two or more slopes 37a, 37b with different inclination angles. Respective slopes 37a, 37b are formed so that a diameter may grow larger from a liquid sealing surface 32 side for sealing up a medicinal solution toward an opposite liquid sealing surface 33 side of an opposite air side between the outer cylinder 2 and itself. Also, two adjacent surfaces of two or more surfaces have at least one relationship in which the inclination angle of the surface of the opposite liquid sealing surface side becomes smaller than an inclination angle of the surface near the liquid sealing surface side.SELECTED DRAWING: Figure 2COPYRIGHT: (C)2016,JPO&INPIT【課題】薬液等が注射器から漏れ出ないように外筒とガスケットとの密封性を向上させる。【解決手段】ゴム材料製の本体4と、本体4の少なくとも外筒2の内周面25と接触する部位31に被覆された慴動性に優れる樹脂フィルム5とを有するシリンジ用ガスケット3において、外筒2の内周面25と接触する少なくとも一つの密封面35を形成し、密封面35は、傾斜角度が異なる複数の傾斜面37a,37bによって構成され、各傾斜面37a,37bが外筒2との間で薬液を密封する液密封面32側からその反対の大気側の反液密封面33側に向かって径が大きくなるように形成されると共に、複数の面のうちの隣接する二つの面が液密封面側寄りの面の傾斜角度よりも反液密封面側の面の傾斜角度の方が小さくなる関係を少なくとも一つ有しているものである。【選択図】図2
