Porous resin bead and method for producing nucleic acid using the same

A porous resin bead comprising a first aromatic monovinyl compound-divinyl compound-(meth)acrylonitrile-second aromatic monovinyl compound copolymer, wherein the second aromatic monovinyl compound contains a group capable of binding with a carboxyl group by dehydration condensation reaction, wherein the porous resin bead has a swelling volume in acetonitrile of from 3 to 6 ml/g, and wherein the amount of a structural unit derived from (meth)acrylonitrile is from 1.8 to 3 mmol/g,

• wherein the first aromatic monovinyl compound is at least one compound selected from the group consisting of nucleus alkyl-substituted styrenes which are styrenes of which benzene ring moiety is substituted, α-alkyl-substituted styrenes, nucleus halogenated styrenes which are styrenes of which benzene ring moiety is halogenated, halogenated alkyl styrenes, hydroxystyrenes, hydroxymethylstyrenes, vinyl benzoates, sodium styrenesulfonates, cyanostyrenes, methoxystyrenes, ethoxystyrenes, butoxystyrenes, nitrostyrenes, and acyloxystyrenes,
• wherein the divinyl compound is at least one compound selected from the group consisting of aromatic divinyl compounds and di(meth)acrylate compounds, and
• wherein the second aromatic monovinyl compound is at least one compound selected from the group consisting of aminostyrene monomers or substitution products thereof, aminoalkylstyrene monomers or substitution products thereof, hydroxystyrene monomers or substitution products thereof, and hydroxyalkylstyrene monomers or substitution product thereof.