PROBLEM TO BE SOLVED: To provide a polymer and a protein adhesion prevention agent capable of forming a coating layer to which protein is less likely to adhere and excellent in water resistance and durability, and a medical device having the coating layer using the protein adhesion prevention agent.SOLUTION: There is provided a polymer having a unit derived from a maleimide derivative having a polyoxyethylene group in a side chain and having glass transition temperature of 20°C or more. There is provided a medical device 1 having a substrate 2 and a coating layer 3 formed on the substrate 2, the coating layer 3 is a layer formed from a protein adhesion prevention agent consisting of the polymer.SELECTED DRAWING: Figure 2【課題】タンパク質が付着しにくく、耐水性および耐久性に優れた被覆層を形成できる重合体およびタンパク質付着防止剤、ならびに該タンパク質付着防止剤を用いた被覆層を備える医療用デバイスを提供することを目的とする。【解決手段】側鎖にポリオキシエチレン基を有するマレイミド誘導体に由来する単位を有する、ガラス転移温度が２０℃以上の重合体。基材２と、基材２上に形成された被覆層３とを備え、被覆層３が、前記重合体からなるタンパク質付着防止剤から形成されてなる層である、医療用デバイス１。【選択図】図２
