An analyzer comprising: a cell containing a reaction solution obtained by mixing of a sample with a reagent; and a light source unit configured to irradiate the cell with a light beam with a first wavelength and a light beam with a second wavelength on the same optical path, the second wavelength being longer than the first wavelength, characterized by a scattered-light light receiving unit configured to receive a scattered light beam with the first wavelength and a scattered light beam with the second wavelength, the scattered light beams (21a, 21b) having been generated by interaction with the reaction solution in the cell; a transmitted-light receiving unit configured to receive a transmitted light beam with the first wavelength and a transmitted light beam with the second wavelength, the transmitted light beams (19a, 19b) having passed through the cell; and a data processing unit, wherein the data processing unit is configured to determine a signal by subtracting, from a signal representing a change in an amount of the scattered light beam with the first wavelength that has changed due to agglutination in the reaction solution, a signal that has been obtained by multiplying a change in an amount of the scattered light beam with the second wavelength by a reagent coefficient that depends on the reagent, and quantitatively determine an amount of a component in the sample on the basis of the determined signal, wherein a ratio between intensities of the transmitted light beam with the first wavelength and the transmitted light beam with the second wavelength is used as the reagent coefficient. a cell containing a reaction solution obtained by mixing of a sample with a reagent; and a light source unit configured to irradiate the cell with a light beam with a first wavelength and a light beam with a second wavelength on the same optical path, the second wavelength being longer than the first wavelength, characterized by a scattered-light light receiving unit configured to receive a scattered light beam with the first wavelength and a scattered light beam with the second wavelength, the scattered light beams (21a, 21b) having been generated by interaction with the reaction solution in the cell; a transmitted-light receiving unit configured to receive a transmitted light beam with the first wavelength and a transmitted light beam with the second wavelength, the transmitted light beams (19a, 19b) having passed through the cell; and a data processing unit, wherein the data processing unit is configured to determine a signal by subtracting, from a signal representing a change in an amount of the scattered light beam with the first wavelength that has changed due to agglutination in the reaction solution, a signal that has been obtained by multiplying a change in an amount of the scattered light beam with the second wavelength by a reagent coefficient that depends on the reagent, and quantitatively determine an amount of a component in the sample on the basis of the determined signal, wherein a ratio between intensities of the transmitted light beam with the first wavelength and the transmitted light beam with the second wavelength is used as the reagent coefficient.