PURPOSE: To prevent the agglomeration of resin particles and static build-up due to friction between the particles, increase mechanical strengths, and improve the wetting between the particles and a matrix resin or a coating material by making dents on the surfaces of the particles during their formation and attaching other finer particles to the dents.

CONSTITUTION: The objective resin particles having various functions are obtd. by adding a functional org. compd. such as a fluorescent colorant, an agrochemical, a medicine, etc., having a wavelength conversion capability to a varnish when it is formed by dissolving granular resin (e.g. polycarbonate) in an org. solvent (e.g. methylene chloride). The varnish is dropped to an aq. soln. of a dispersant (e.g. polyvinyl alcohol) under stirring to form an emulsion. The particle size of the emulsion is controlled to 100-300μm, giving resin particles with highly uneven surfaces. Addition of finer particles (e.g. colloidal silica) to the aq. soln. of the dispersant or during the formation of the emulsion causes the finer particles to attach to dents of the resin particles.