PURPOSE: To improve the fluid introduction and the adsorption by arranging an adsorption layer in which fibrous, filamentary, or wiry adsorbents are packed in a high porosity and all or the greater part of the fluid is introduced obliquely.

CONSTITUTION: An adsorption layer 2 is constituted by adsorptive substance 4 contained in a vessel having a fluid passage such as lattice 3. The adsorptive substance 4 consists of an adsorbent or an adsorptive body. The adsorbent is formed in a fibrous, filamentary or wiry shape having a hardness not to produce a deformation during the operation, and a size not to pass through the lattice so as to be packed in high porosity. In case of the adsorptive body, the adsorbent formed to a fibrous, fulamentary or wiry shape is wrapped with a reticular body to obtain a high void ratio and is covered further with a material for adjusting a specific gravity of the covered body in case of need.