The present invention is to provide a method of producing a separating agent for an enantiomeric isomer having a high optical resolution power together with sufficient solvent resistance. That is, a method of producing a separating agent for an enantiomeric isomer comprising the steps of allowing the porous carrier to carry the optically active polymer compound by bringing the porous carrier into contact with a dope of the optically active polymer compound and exposing a product to radiation.