The present invention relates to a method for producing a porous resin particle containing an aromatic vinyl compound-aromatic divinyl compound copolymer having a hydroxyl group, the method including: dissolving a monomer mixture containing an aromatic vinyl compound, an aromatic divinyl compound and a (meth)acrylic acid ester having one hydroxyl group within the molecule thereof, 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; and performing a suspension copolymerization. The method of the invention is capable of easily producing a porous resin particle containing an aromatic vinyl compound-aromatic divinyl compound copolymer having a hydroxyl group, that is used as a support for solid phase synthesis and enables efficient nucleic acid synthesis.