PURPOSE: To allow a soluble arbitrary compound to be contained in a porous particle, by simple operation such that said compound is dissolved in a solvent having a b.p. lower than that of the compound and the resulting solution is infiltrated in a hollow porous particle to evaporate the solvent.

CONSTITUTION: A compound is dissolved in a proper solvent and, for example, in case of vitamins, each of them is dissolved in alcohol or ether and the resulting solution is infiltrated in a hollow porous particle. When a silica hollow porous particle is used, the silanol group on the surface of the particle is converted to siloxane by preheating. After impregnation, the solvent is removed by a vacuum degassing method to obtain a compound containing porous particle. By this method, the anti-oxidation property of an oxidizable substance is enhanced and its controlled release property can be obtained and a compound in a solution form can be handled as powder.