PROBLEM TO BE SOLVED: To solve such a problem that rubber elasticity of a laminate gasket is essential for reliably sealing a drug solution, however, it has a drawback that, when the rubber elasticity is insufficient, the drug solution is leaked from a syringe, and address the necessity for further improvement in slidability when the gasket is inserted into the syringe.SOLUTION: A gasket 13 applied to a medical syringe includes a body 14 composed of an elastic body, and a laminate film 15 superposed on a surface of the body 14. The gasket 13 has a circumferential surface part 17 coming into contact with an inner peripheral surface of the syringe 11, and the laminate film 15 disposed on the circumferential part 17 includes a groove 22 extending in the circumferential direction, formed on the film surface. The gasket 13 is characterized in that, when the thickness of the laminate film 15 disposed on the circumferential surface part 17 is D [μm], the depth of the groove 22 is 0.8D [μm] or more, preferably D [μm] or more.SELECTED DRAWING: Figure 3COPYRIGHT: (C)2017,JPO&INPIT
