The objectives of this invention are to provide a filler for separating optical isomers, capable of efficiently carrying out optical resolution of optical isomer mixtures, and to provide a process for separating optical isomers by a simulated moving bed chromatography utilizing the filler. This invention provides a filler made of a carrier supporting a specific amount of an optically active high molecular weight compound. Separation by the simulated moving bed chromatography using the filler is carried out under the condition that the capacity factors have specific values.