A liquid chromatography apparatus, comprising: a sample preparation unit for preparing a sample from a specimen; a column for separating components of the sample; an eluent supplier (3, 4) for supplying as a mobile phase two or more types of eluent (La, Lb) to the column; a first flow path directional valve capable of introducing a fixed amount of the sample to the column and capable of introducing the eluent to the column; an analyzer for analyzing a test solution composed of the sample components separated by the column and the eluent; and a controller for controlling operation of the sample preparation unit, the eluent supplier (3, 4), the first flow path directional valve and the analyzer; wherein the eluent supplier (3, 4) supplies two or more types of eluent (La, Lb) to the first flow path directional valve in an unmixed state, and wherein the eluent supplier (3, 4) is provided with a second flow path directional valve that is able to supply to the first flow path directional valve first and second eluents (La, Lb) mutually supplied to separate ports, characterized in that the second flow path directional valve is capable of accumulating a fixed amount of the second eluent (Lb); and in that the controller is configured to carry out control so that at least a portion of the fixed amount of the second eluent (Lb) accumulated in the second flow path directional valve and the first eluent (La) subsequently introduced into the second flow path directional valve from a port different from that of the second eluent are supplied to the column through the first flow path directional valve either during or after analysis of the test solution by supplying the first eluent (La) to the column through the first flow path directional valve. a sample preparation unit for preparing a sample from a specimen; a column for separating components of the sample; an eluent supplier (3, 4) for supplying as a mobile phase two or more types of eluent (La, Lb) to the column; a first flow path directional valve capable of introducing a fixed amount of the sample to the column and capable of introducing the eluent to the column; an analyzer for analyzing a test solution composed of the sample components separated by the column and the eluent; and a controller for controlling operation of the sample preparation unit, the eluent supplier (3, 4), the first flow path directional valve and the analyzer; wherein the eluent supplier (3, 4) supplies two or more types of eluent (La, Lb) to the first flow path directional valve in an unmixed state, and wherein the eluent supplier (3, 4) is provided with a second flow path directional valve that is able to supply to the first flow path directional valve first and second eluents (La, Lb) mutually supplied to separate ports, characterized in that the second flow path directional valve is capable of accumulating a fixed amount of the second eluent (Lb); and in that the controller is configured to carry out control so that at least a portion of the fixed amount of the second eluent (Lb) accumulated in the second flow path directional valve and the first eluent (La) subsequently introduced into the second flow path directional valve from a port different from that of the second eluent are supplied to the column through the first flow path directional valve either during or after analysis of the test solution by supplying the first eluent (La) to the column through the first flow path directional valve.