PURPOSE: To improve low addition reaction efficiency due to uneven addition reaction of an amino acid by a graft-polymerizing polymerizable amino acid- bonded monomer obtained by the reaction of a polymerizable monomer and an amino acid, on a polymer material membrane.

CONSTITUTION: An amino acid-bonded polymerizable monomer obtained by the reaction of a polymerizable monomer having a group reactive with an amino acid and a amino acid is graft-polymerized on a polymer material membrane to give a functional membrane. The polymer material membrane is a membrane of a polymer or a compolymer of an olefin and a halogenated olefin. The amino acid-bonded polymerizable polymer is an addition polymer of an amino acid and glycidyl methacrylate, glycidyl acrylate, glycidyl sorbate, glycidyl methaitaconate, ethylglycidyl maleate, or glycidyl vinylsulfonate. The polymerizable monomer is further graft-polymerized on a polymer material membrane to produce a functional membrane.