disclosed is a liquid chromatograph provided with : a first flow path switching means which switches between connection of a sample storage loop to a mobile phase flow path and separation of the sample storage loop from the mobile phase flow path ; a needle which suctions and discharges a sample ; a weighing means which performs suction and discharge of the sample to the needle while weighing the sample ; a cleaning solution feeding means which feeds a cleaning solution ; a second flow path switching means which switches between at least two types of cleaning solutions ; a third flow path switching means which switches between connection of the needle and the weighing means and connection of the needle and the cleaning solution feeding means ; and a control means which controls operation of the first flow path switching means , the weighing means , the cleaning solution feeding means , the second flow path switching means , and the third flow path switching means , wherein the total amount of the sample is injected into the sample storage loop and the cleaning solution is injected into a flow path from the sample storage loop to a sample inlet .