A process for easily producing a packing material for high-performance liquid chromatography, which produces only a small amount of a dissolved matter. The process has a low cost and contributes to an improvement in the quality of the separated product, without reducing the separation capacity in the field of the separation of only a small amount of a dissolved matter derived from the polysaccharide derivative is obtained by washing the packing material comprising a polysaccharide coated on a carrier with a solvent.