NOVELTY - The gas storage method of a gas storage medium (100) having a multilayer structure in which crystalline structures (120) are stacked to be spaced from each other, comprises selectively storing gas by relatively controlling a space between the crystalline structures or a lattice distance between crystals of each crystalline structure with respect to the van der Waals diameter of gas which is to be stored. The crystalline structure has a layered or cubical structure. The crystalline structure is a vanadium pentoxide crystalline structure.    USE - The method is useful for storing gas such as hydrogen in a medium, where the hydrogen is useful as an energy source and/or as a basic industrial material and a domestic fuel for hydrogen vehicles and fuel cells    ADVANTAGE - he method increases gas storage efficiency with improved hydrogen storing ability.    DETAILED DESCRIPTION - The gas storage method of a gas storage medium (100) having a multilayer structure in which crystalline structures (120) are stacked to be spaced from each other, comprises selectively storing gas by relatively controlling a space between the crystalline structures or a lattice distance between crystals of each crystalline structure with respect to the van der Waals diameter of gas which is to be stored. The crystalline structure has a layered or cubical structure. The crystalline structure is a vanadium pentoxide crystalline structure. The space between the crystalline structures or the lattice distance between crystals of each crystalline structure is controlled by changing the temperature of a heat treatment of the gas storage medium. The space between the crystalline structures or the distance between crystals of each crystalline structure is controlled by introduction of a chemical reaction group during sample synthesis of the gas storage medium. The chemical reaction group is an organic compound containing an amine group. The crystalline structure is formed in such a shape that crystals are consecutively joined to form one crystalline structure as a whole. The crystalline structure includes a transition metal, a compound with a transition metal, or a transition metal oxide.    DESCRIPTION OF DRAWING(S) - The diagram shows a perspective view of a gas storage medium.    Gas storage medium (100)    Crystalline structures. (120)