Provided is a novel polysaccharide derivative having a main structure of the following formula (1) in which a polysaccharide or its derivative has been chemically bonded to the inner and outer surfaces of the pores of a porous carrier at the reducing terminal of the polysaccharide or polysaccharide derivative: ##STR1## Also provided are a method of producing the novel polysaccharide derivative in which a silane agent is chemically bonded to a porous carrier and thereafter a polysaccharide having a degree of polymerization from 11 to 500 or its derivative is further chemically bonded to surface treated carrier at the reducing terminal of the polysaccharide or its derivative, and a method of producing the novel polysaccharide derivative in which a polysaccharide having a degree of polymerization from 11 to 500 or its derivative is chemically bonded to a silane agent at the reducing terminal of the polysaccharide or its derivative and thereafter the polysaccharide derivative is further chemically bonded to a porous carrier. Further provided is a separating agent for chromatography containing the novel polysaccharide derivative. The novel polysaccharide derivative has excellent solvent resistance and is useful as a separating agent for chiral resolution of chiral compounds by chromatography. The methods of the present invention efficiently give the novel polysaccharide derivative.