Disclosed is a method of producing an optically active &bgr;-hydroxy sulfonic acid compound comprising hydrogenating a &bgr;-keto sulfonic acid compound represented by formula 1: where R1 represents an alkyl or a phenyl group, which may be substituted, and R2 represents sodium or an alkyl group, in an acidic solvent, in the presence of an asymmetric catalyst comprising a complex of bivalent Ru, having 2,2′-bis(diphenylphosphino)-1,1′-binaphthyl as a ligand, to produce a compound represented by formula 2: where R1 and R2 are as defined above, and * designates an asymmetric carbon atom.