To make it possible to manufacture a packaging material using a single layer structure of a polydimethyl ketone type which is provided with the property of functioning as a barrier against an oxygen regardless of all properties, required for using in the aqueous or moist medium, that are a non-transmission nature or water-proofness, an inactiveness(characteristic that physical and mechanical properties do not change under presence of water) against a water, property not absorbing water and medium humidity.

The structure includes at least one layer of a polymer (A) whose base is the poly(dimethyl ketone). For the most moist medium, (i) in the case of the packaging material containing a water or aqueous solution or moist product, the layer of the polymer (A) is present inside of the packaging material, (ii) in the case of the packaging material containing a dried product or product to be protected from moisture, the layer of the polymer (A) is present outside of the packaging material.