Abstract: A membrane type artificial lung uses a gas-exchange membrane having at least the surface thereof for exposure to blood or the minute pores therein coated or blocked with a vinyl type copolymer having as one of the components thereof a vinyl monomer possessing a perfluoroalkyl side chain. The gas-exchange membrane of the artificial lung is manufactured by a method which comprises bringing at least the surface of the gas-exchange membrane for exposure to blood into contact with a solution of the vinyl type copolymer and subsequently vaporizing the solvent in the solution.

Abstract: In a membrane type artificial lung using as gas-exchange membranes porous hydrophobic membranes having a wall thickness in the range of 5 to 80 .mu.m, a porosity in the range of 20 to 80%, and a pore diameter in the range of 0.01 to 5 .mu.m, the minute pores of the membranes are blocked with minute particles of silica having a diameter smaller than the pore diameter and having a hydrophobic surface at least on the sides thereof intended for exposure to blood. Optionally, the gas-exchange membranes have the surfaces for exposure to blood coated with a biocompatible hydrophobic resin.