Providing sliding members with excellent durability that can maintain wear resistance over a long period of time. Providing an artificial joint member with a thin polymer substrate. Providing an artificial joint that can exhibit high lubricity, biocompatibility, and anti-dislocation after being taken into the body. Providing medical device materials and medical devices that exhibit excellent biocompatibility. The sliding material or the medical device material is formed by covering at least a part of the surface of the polymer base material (A) having a ketone group on the surface thereof and providing a polymer layer or a biocompatible material layer (B). The polymer layer or biocompatible material layer (B) is obtained by immersing the polymer substrate (A) in a reaction system containing the monomer (C) and irradiating the polymer substrate (A) with light. It is formed by surface graft polymerization that initiates polymerization of monomers from the surface of the substrate (A). An artificial joint member, an artificial joint, a medical instrument material, and a medical instrument are produced using such a sliding material or a medical instrument material.長期間にわたって耐摩耗性を維持できる、耐久性に優れた摺動部材の提供。ポリマー基材の薄厚化を図った人工関節部材の提供。体内に取り込んだ後に、高潤滑性、生体適合性、抗脱臼性を示すことができる人工関節の提供。優れた生体適合性を示す医療器具材料及び医療器具の提供。摺動材料または医療器具材料は、ケトン基を表面に有するポリマー基材（Ａ）の少なくとも一部の表面を被覆してポリマー層または生体適合性材料層（Ｂ）が設けられて形成されており、該ポリマー層または生体適合性材料層（Ｂ）は、モノマー（Ｃ）を含む反応系にポリマー基材（Ａ）を浸漬し、ポリマー基材（Ａ）に対して光を照射して、ポリマー基材（Ａ）の表面からモノマーの重合を開始させる表面グラフト重合によって形成されることを特徴とする。かかる摺動材料または医療器具材料を用いて、人工関節部材、人工関節、医療器具材料及び医療器具を作製する。
