The present invention is the method for preparation of transition metal oxide having micro-mesoporous structure whose average fine pores size is not less than 1 nm and not more than 2 nm comprising, adding and dissolving transition metal salt which is a precursor of transition metal oxide and/or metal alkoxide in the solution prepared by dissolving polymer surfactant in organic solvent, hydrolyzing said transition metal salt and/or metal alkoxide and preparing sol solution which is polymerized and self organized, then obtaining gel whose organization is stabilized from said sol solution and removing said polymer surfactant by using water of room temperature or water to which alkali metal or alkaline earth metal ion is added.