PROBLEM TO BE SOLVED: To provide a method for modifying the surface of vulcanized rubber and a gasket for a syringe capable of imparting various functionalities such as slidability, liquid leakage resistance, and protein adsorption suppression property. SOLUTION: The surface modification method uses a vulcanized rubber having a Shore A hardness of 55 to 90 as an object to be modified, and a step 1 of adding a silane compound to the surface of the object to be modified, and at least a fluoroalkyl group. And a step 2 of forming a surface-modified layer by reacting the contained silane compound. [Selection diagram] None【課題】摺動性、耐液漏れ性、タンパク質吸着抑制性などの様々な機能性を付与できる加硫ゴムの表面改質方法、及び注射器用ガスケットを提供する。【解決手段】ショアＡ硬度５５～９０の加硫ゴムを改質対象物とする表面改質方法であって、前記改質対象物の表面にシラン化合物を付加させる工程１と、少なくともフルオロアルキル基含有シラン化合物を反応させて、表面改質層を形成する工程２とを含むことを特徴する表面改質方法。【選択図】なし
