The present invention provides a method for producing an artificial lung having a plurality of gas exchange porous hollow fiber membranes having an outer surface, an inner surface forming a lumen, and an opening communicating the outer surface with the inner surface. A method for producing an artificial lung, comprising a step of bringing one of the outer surface and the inner surface into contact with a colloid solution containing an antithrombotic polymer compound and flowing carbon dioxide gas to the other surface side. About. ADVANTAGE OF THE INVENTION According to this invention, the artificial lung which increased the coating amount of the antithrombotic polymeric material (antithrombotic polymeric compound) with respect to a hollow fiber membrane can be manufactured.本発明は外表面と、内腔を形成する内表面と、前記外表面と前記内表面とを連通する開口部と、を有する複数のガス交換用多孔質中空糸膜を有する人工肺の製造方法であって、前記外表面及び前記内表面のいずれか一方を、抗血栓性高分子化合物を含むコロイド溶液と接触させ、他方の表面側に炭酸ガスを流通させる工程を有する、人工肺の製造方法に関する。本発明によれば、中空糸膜に対する抗血栓性高分子材料（抗血栓性高分子化合物）のコート量を増加させた人工肺を製造できる。
