To provide a cation exchanger for liquid chromatography having a high retention for an object to be separated or analyzed, a sufficient binding capacity for the object, a high resolution and mechanical strength, and a low operation pressure. A cation exchanger for liquid chromatography, comprising non-porous particles and, immobilized to the surface thereof, a polyacrylic acid into which a dicarboxylic acid compound having an amino group is introduced by an amide bond.
