The present invention provides, as a resin bead which can be developed for use completely different from the use of conventional polystyrene resin beads, a porous resin bead made from a styrene-hydroxystyrene-divinylbenzene copolymer, which contain a hydroxyl group in an amount of 10 1000 .mu.mol/g, and further, a production method of a porous resin bead made from a styrene-hydroxystyrene-divinylbenzene copolymer, which contains suspension copolymerization of a styrene monomer, an acyloxystyrene monomer and a divinylbenzene monomer using an organic solvent (containing at least hydrocarbon and alcohol) and water, followed by hydrolysis reaction.