PURPOSE: To generate porous organic fine particles having uniform size by generating sol of organic colloidal particles in polar liquid, and generating mixture of organic material polymerizable with formaldehyde with sol.

CONSTITUTION: The sol of inorganic colloidal particles in polar liquid is generated. The colloidal particles have hydroxylated surfaces, and can be dispersed in the liquid. Then, the mixture of organic material polymerizable with second organic material selected from a group consisting of formaldehyde, urea and melamine and the sol is generated. The polymerization of the material in the mixture is started to cause coacervation of the organic material and colloidal particles to fine particles having size of about 0.5 to 20 micron. The thus formed fine particles are exposed with solution of reagent of sufficient concentration to remove all inorganic components of suitable composition. Thus, the fine particles having uniform size can be generated.