PROBLEM TO BE SOLVED: To provide a gasket having excellent performance such as slidability and liquid leak resistance.SOLUTION: The present invention provides a gasket 2 with a polymer chain 21 immobilized to at least part of a base material gasket surface, and including a plurality of annular projection parts on a slide face 14. Out of the annular projection parts, a first projection part 14a closest to a top face 12 has surface roughness Ra of 1.0 or less.SELECTED DRAWING: Figure 2【課題】摺動性、耐液漏れ性等の性能に優れたガスケットを提供する。【解決手段】基材ガスケット表面の少なくとも一部にポリマー鎖２１が固定化され、摺動面１４に複数の環状突出部を有するガスケット２であって、前記環状突出部のうち、天面１２に最も近い第１突出部１４ａの表面粗さＲａが１．０以下であるガスケット。【選択図】図２
