TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Layer: Layer (Y) is layer (YA) containing reaction product (R) of aluminum-containing metal oxide and phosphorus compound. In the infrared absorption of layer (YA), the largest wave number (n1) is at 1080-1130 cm-1 in a range of 800-1400 cm-1. The ratio of absorbency at wave number (n2) and absorbency at wave number (n1) is 0.2 or less, where wave number (n2) is largest wave number in infrared absorption base on stretching vibration of hydroxyl group in the range of 2500-4000 cm-1 in the infrared absorption spectrum of layer (YA). The half value width of absorption peak of wave number (n1) is 200 cm-1. The ratio of number of moles of metal atom of metal oxide in layer (YA) with respect to the number of moles of phosphorus atom derived from the phosphorus compound is 3.6 or less. Layer (Y) is vapor deposition layer of aluminum (oxide). The base material is thermoplastic resin film layer, paper layer, and/or inorganic vapor deposition layer. A coating liquid containing the metal oxide, solvent, and compound(s) having a site reactive with the metal oxide, is prepared. The coating liquid is applied on the base material to form a precursor layer of layer (YA). The precursor layer is heated at 140 degrees C or more to form layer (YA), followed by formation of layer (Z). Preferred Compounds: The phosphorus compound is phosphoric acid, polyphosphoric acid, phosphorus acid, phosphonic acid, and/or their derivatives.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Compound: The metal oxide is hydrolysis condensation product of a compound containing a metal atom which can be hydrolyzed and coupled, which contains compound(s) of formula: Al(X1)m(R1)3-m, preferably aluminum triisopropoxide and/or aluminum tri-s-butoxide.X1=F, Cl, Br or I;R2=O-, R3C(=O)O-, (R4C(=O))2CH-, or NO3;R1-R4=alkyl, aralkyl, aryl or alkenyl;andm=1-3.    TECHNOLOGY FOCUS - POLYMERS - Preferred Properties: The multilayered structure has a structure given by, base material/layer (Y)/layer (Z). The multilayered structure has an oxygen permeability of 2 ml/(m2.day.atm) or less at 20 degrees C and 85% relative humidity, and 4 ml/(m2.day.atm) or less at same conditions after stretching at a rate of 5% at 23 degrees C and 50% relative humidity. Preferred Components: The polymer is a homopolymer or a copolymer containing a side chain whose terminal is phosphoric acid group or its (meth)acrylic acid ester. The polymer is preferably a homopolymer of acid phosphoxyethyl methacrylate.