The automatic analysis device measures time sequential data on a scattered light amount as reaction process data, and quantitatively determines the concentration of an analyte from a change in light amount. The automatic analysis device has a function of selecting reaction process data to be used for quantitative determination from the reaction process data obtained by measurement using a plurality of light receivers at different angles. As a result of using this function, data is selected from the reaction process data obtained by measurement using the plurality of light receivers at different angles in accordance with the concentration of the analyte and whether the priority is given to high sensitivity in the case where sensitivity is prioritized or a dynamic range, and the result of the quantitative determination is displayed.