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, a process for producing the filler, and a method for using the filler. The present invention provides a process for producing a filler for separating optical isomers which process comprises stirring a carrier and a solution including an optically active polymer compound with a double spindle vertical mixer. The present invention further provides a filler produced by the process and a method for using the filler in liquid chromatographic separation methods and simulated moving bed chromatographic separation methods.