PROBLEM TO BE SOLVED: To provide a technique capable of improving durability as compared with polymethoxyethyl acrylate and forming a film on a substrate regardless of the type of a constituent material of a base material. SOLUTION: The artificial lung 1 has a plurality of porous hollow fiber membranes for gas exchange 3 made of a hydrophobic polymer material, and the inner surface or the outer surface of the hollow fiber membrane is 70 mol% or more and 90 mol. Includes a copolymer having a structural unit derived from alkoxyalkyl (meth) acrylate of% or less and a structural unit derived from hydroxyalkyl (meth) acrylate of 10 mol% or more and 30 mol% or less and having a weight average molecular weight of 200,000 or more. An artificial lung covered with a capsule. [Selection diagram] Fig. 1【課題】ポリメトキシエチルアクリレートより耐久性を向上でき、基材の構成材料の種類によらず、基板に被膜を形成できる技術を提供する。【解決手段】疎水性高分子材料からなる複数のガス交換用多孔質中空糸膜３を有する人工肺１であって、前記中空糸膜の内表面または前記外表面が、７０モル％以上９０モル％以下のアルコキシアルキル（メタ）アクリレート由来の構成単位および１０モル％以上３０モル％以下のヒドロキシアルキル（メタ）アクリレート由来の構成単位を有しかつ重量平均分子量が２０万以上の共重合体を含む被膜で被覆される人工肺。【選択図】図１
