A porous structure includes an organic metal complex represented by the following general formula (1):
M·L(A,B)
3
(1)
(where M represents a metal atom; L (A, B) represents a ligand constituted of A and B; and A and B respectively represent cyclic groups which may have or may not have one or more substituents).
A gas separation method for separating a specific component gas from a mixed gas using an adsorbent comprises (1) a contact step of bringing a mixed gas into a vessel to contact at a first pressure the mixed gas with an adsorbent whose adsorption property with respect to a specific component gas exhibits hysteresis, (2) a decompression step of decompressing the mixed gas in the vessel to a second pressure which is lower than the first pressure and which is within the hysteresis range, and (3) a desorption step of causing adsorbed matter to detach by placing the adsorbent at a third pressure which is lower than the second pressure and which is outside of the hysteresis range and/or by heating the adsorbent.