Abstract: This invention provides an ultra-micro simulated moving bed apparatus employing valve devices, each of which is applied to each unit column and comprises an eluent valve that opens or closes a first communication passage connecting an eluent feeding cul-de-sac passage with the circulation passage, an extract valve that opens or closes a second communication passage connecting an extract draw-out cul-de-sac passage with the circulation passage, a feedstock mixture valve that opens or closes a third communication passage connecting a feedstock mixture feeding cul-de-sac passage with the circulation passage, and a raffinate valve that opens or closes a fourth communication passage connecting a raffinate draw-out cul-de-sac passage with the circulation passage.