A plastic film for use as a medical container which is composed of at least five layers, formed by a water-cooling inflation method of co-extrusion, and has an oxygen absorbing function, comprising in order starting with the outermost layer: a first layer that contains a polyamide obtained from a ring-opening polymerization of a lactam having 11 or 12 carbon atoms or from polycondensation of an ω-amino acid having 11 or 12 carbon atoms, or a polyamide obtained from copolycondensation of a dicarboxylic acid having 10 to 12 carbon atoms and a diamine having 6 or more carbon atoms; a second layer that is adjacent to the first layer and contains a copolymer of an α-olefin and a monomer of an unsaturated carboxylic acid or an anhydride of an unsaturated dicarboxylic acid as the major component; a third layer that is adjacent to the second layer and contains as the main component an ethylene vinyl alcohol copolymer and as accessory components a transition metal salt and a polyene-based polymer having an unsaturated double bond; a fourth layer that is adjacent to the third layer and contains a copolymer of an α-olefin and a monomer of an unsaturated carboxylic acid or an anhydride of an unsaturated dicarboxylic acid as the major component; and a two-layer sealing layer, wherein one layer is adjacent to the fourth layer and is set to be a mixture of 60 to 95 mass% of linear low-density polyethylene (LLDPE) and 5 to 40 mass% of high-density polyethylene (HDPE), and another layer is a direct-melt sealing layer that only includes HDPE, and wherein a thickness ratio of said one layer to said other layer is in the range of 50 to 97: 50 to 3, wherein the melting peak temperature of the first layer is 175 °C or higher, and the difference between the melting peak temperature of the first layer and the melting peak temperatures of the sealing layers is 40°C or larger, wherein the thickness of the first layer is 2 to 15 % of the total thickness. a first layer that contains a polyamide obtained from a ring-opening polymerization of a lactam having 11 or 12 carbon atoms or from polycondensation of an ω-amino acid having 11 or 12 carbon atoms, or a polyamide obtained from copolycondensation of a dicarboxylic acid having 10 to 12 carbon atoms and a diamine having 6 or more carbon atoms; a second layer that is adjacent to the first layer and contains a copolymer of an α-olefin and a monomer of an unsaturated carboxylic acid or an anhydride of an unsaturated dicarboxylic acid as the major component; a third layer that is adjacent to the second layer and contains as the main component an ethylene vinyl alcohol copolymer and as accessory components a transition metal salt and a polyene-based polymer having an unsaturated double bond; a fourth layer that is adjacent to the third layer and contains a copolymer of an α-olefin and a monomer of an unsaturated carboxylic acid or an anhydride of an unsaturated dicarboxylic acid as the major component; and a two-layer sealing layer, wherein one layer is adjacent to the fourth layer and is set to be a mixture of 60 to 95 mass% of linear low-density polyethylene (LLDPE) and 5 to 40 mass% of high-density polyethylene (HDPE), and another layer is a direct-melt sealing layer that only includes HDPE, and wherein a thickness ratio of said one layer to said other layer is in the range of 50 to 97: 50 to 3, wherein the melting peak temperature of the first layer is 175 °C or higher, and the difference between the melting peak temperature of the first layer and the melting peak temperatures of the sealing layers is 40°C or larger, wherein the thickness of the first layer is 2 to 15 % of the total thickness.