To provide a chromatography separator of an intermittent mobile bed type or a pseudo-mobile bed type, which can stably maintain the purity of a separated component.

In the chromatography separator, four or more columns 14 are connected to form a circulation path 16. A raw liquid containing an element A and an element C and an eluent are injected into the circulation path 16, and are then circulated in the circulation path 16. A concentration detector 54 is provided in a position adjacent to a valve 41 for drawing the component A in the circulation path 16, and the concentration of the component in the circulation path 16 is detected in the circulation process. When the concentration of the component reaches or exceeds a prescribed concentration, it is judged that the component A is separated from the component C in the raw liquid and the step goes from the circulation process to the next component drawing process.