PURPOSE: To form a spherical particle having amine functionality but no positive ion exchange functionality by copolymerization of a monomer mixture of amine containing monomer and cross link type monomer.

CONSTITUTION: A monomer mixture obtained by mixing 159 g water-soluble dimethylaminopropylmethacrylamide, 8.36 g high purity divinylbenzene, and 0.836 g diethyleneglycolevinylether are mixed with a xylene starting agent solution, transferred to a reaction chamber and the liquid component is extracted from the solid by continuing stirring for 20 hours at 52°C. Then, an obtained anion exchange resin bead obtained by washing the solid by water and removing salt and most of xylene is porous and spherical without containing coagulated or deformed particles. Consequently the resin containing no residual cation exchange capacity essentially may reduce a necessary volume for washing than a resin by the conventional method.