Abstract: A liquid chromatograph includes: a concentration column for capturing a target component; an analysis column for separating the target component from other components; first passage-switching units for switching between the state of forming a passage through which a sample-introduction mobile phase containing the liquid sample is fed to the concentration column, and the state of forming a passage through which an eluant for eluting the target component captured in the concentration column is fed to the concentration column; a storage unit for storing the eluant; and a second passage-switching unit for switching between the state of forming a passage through which an analysis mobile phase is fed to the analysis column and a passage through which the eluant from the concentration column is fed to the storage unit, and the state of forming a passage through which analysis mobile phase is fed to the analysis column via the storage unit.