To provide a new porous resin bead applicable to a use quite different from the use of conventional polystyrene resin bead based on a new action by designing the porous resin according to a new development guideline, and provide a method for producing the porous resin bead.

The porous resin bead is composed of a styrene-hydroxystyrene-divinylbenzene copolymer and has a hydroxy value of 10-1,000μmol/g. The porous resin bead composed of the styrene-hydroxystyrene-divinylbenzene copolymer is produced by carrying out the suspension copolymerization of a styrenic monomer, an acyloxystyrenic monomer and a divinylbenzene monomer using an organic solvent (at least containing a hydrocarbon and an alcohol) and water, and subjecting the copolymerization product to hydrolysis reaction.