To obtain porous silica particles whose pore surfaces coated with an organic compound through omitting a surfactant-removing step.

The flaky or fibrous organic/inorganic porous silica particles are obtained by the following process: In a strongly acidic reaction system using an inexpensive alkali silicate as silica source in the presence of a nonionic surfactant, the system is put to aging at 60°C or higher for forming a high-order regular structure in particular by controlling both the kind of and the method for adding a metal element, and the solid formed by the reaction is dried. The porous silica particles thus obtained are such that the pore surfaces are coated with the surfactant or the organic groups or organic molecules derived from the surfactant.

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