PURPOSE: To prevent the loss of oxygen barrier characteristics by providing one moisture barrier polymer layer at least on oxygen barrier polymer layer having oxygen permeability depending on water content and bonding these layers according to circumstances by an adhesive layer and positioning the oxygen barrier polymer layer on the outside of a structure.

CONSTITUTION: A moisture barrier polymer layer and an oxygen barrier polymer layer having oxygen permeability depending on humidity are provided and these layers are bonded by an adhesive according to circumstances and the oxygen barrier polymer layer is positioned on the outside of a structure. The oxygen barrier polymer layer is especially useful when it contains a vinyl alcohol/ethylene copolymer EVOH or comprises EVOH. The moisture barrier layer comprises polyolefin and other arbitrary polymer generally used in the packaging of food or medicines, especially, a simultaneously extrudable polymer. By arranging the EVOH layer outside, the water content of EVOH becomes equal to humidity of air, that is, becomes min. at a place where a packed product is stored and, therefore, EVOH develops the capacity as an effective oxygen barrier polymer maximally.