it is possible to present invention relates to liquid flows smoothly bypass groove, to provide a dual chamber combined container-syringe, which can reduce the amount of liquid remaining in the bypass groove. Outer tube as well as form a cylindrical shape whose inner diameter is uniform over the shaft line O direction around the [SOLUTION] axis O, with a bypass groove 11a which is molded in the recessed from the inner peripheral surface part of the axis O and a 10, the inner diameter of the outer tube 10 is a 6.0mm or 10.0mm or less, the bypass groove 11a is more molded at intervals in the circumferential direction of the axis O, cross-sectional area perpendicular to the axis O of the bypass groove 11a There is 0.24% or less 0.13% or more of the circumferential cross-sectional area within which is orthogonal to the axis O of the outer cylinder 10, the depth of the bypass groove 11a recessed from the inner circumferential surface 2 of the inner diameter of the outer cylinder 10. it is 3.8% or less by more than 7%. [Selection Figure] Figure 1【課題】液剤がバイパス溝を円滑に流通することができるとともに、該バイパス溝内に残留する液剤の量を低減できる二室式容器兼用注射器を提供する。【解決手段】軸線Oを中心として内径が該軸線O方向にわたって一様とされた円筒形状をなすとともに、軸線O方向の一部に内周面から凹むようにして成型されたバイパス溝11aを有する外筒10を備え、外筒10の内径が6.0mm以上10.0mm以下とされ、バイパス溝11aは軸線Oの周方向に間隔をあけて複数成型され、バイパス溝11aの軸線Oに直交する断面積が、外筒10の軸線Oに直交する内周断面積の0.13%以上0.24%以下とされ、内周面から凹むバイパス溝11aの深さが、外筒10の内径の2.7%以上3.8%以下とされている。【選択図】図1
