PURPOSE: To provide spherical particle of a polymer having amino group at side chain and modified by ionic adsorption with a compound having anionic group and useful for coloring, imparting of ultraviolet absorptivity, prevention of chapped skin, etc., as an additive for cosmetic, soap, shampoo, etc.

CONSTITUTION: The objective spherical polymer particle has an average particle diameter of 0.1W100μm (preferably 0.2W70μm), contains amino group at side chain and modified by ionic adsorption with a compound having anionic group (e.g. sulfone group, carboxyl group, phenolic OH group, etc.) such as acidic dye, ultraviolet absorber, L-ascorbic acid, colorant for food, colorant for cosmetic, colorant for quasi-drug, etc. The polymer is chitosan or a copolymer containing acrylic monomer or aromatic vinyl monomer having amino group. A cosmetic having high bleed-out resistance can be produced by the use of the polymer particle. The particle exhibits a function of slow-releasing agent by contacting with an aqueous solution of NaCl, etc.