Abstract: The present invention provides a method for producing a porous resin bead containing an aromatic vinyl compound-hydroxystyrene-di(meth)acrylate copolymer, the method including: dissolving a monomer mixture containing an aromatic vinyl compound, an acyloxystyrene and a di(meth)acrylate compound, and a polymerization initiator in an organic solvent to obtain a solution containing the monomer mixture and the polymerization initiator; suspending the solution in water in the presence of a dispersion stabilizer; performing a suspension copolymerization to thereby obtain an aromatic vinyl compound-acyloxystyrene-di(meth)acrylate compound copolymer; and hydrolyzing an acyloxy group of the acyloxystyrene monomer component in the copolymer. The porous resin bead produced by the method of the present invention can be suitably used, for example, as a support for solid phase synthesis.