A plastic film (10) which comprises at least three layers, i.e., a first layer (1) comprising a polyamide produced by the ring-opening polymerization of a lactam having 11 or more carbon atoms or the polycondensation of an ω-amino acid having 11 or more carbon atoms or a polyamide produced by the co-polycondensation of a dicarboxylic acid having 10 or more carbon atoms and a diamine having 6 or more carbon atoms, a second layer (2) mainly composed of a copolymer of an α-olefin and an anhydride monomer of an unsaturated carboxylic acid or an unsaturated dicarboxylic acid, and a sealing layer (3) mainly composed of polyethylene, and which is produced by a co-extrusion method and an infusion bag comprising the plastic film (10).
