PURPOSE: To obtain a grain constituent analyzer which can analyze constituents by using a proper calibration equation corresponding to changes even if samples with different brand and type of a sample grain are supplied.

CONSTITUTION: The title analyzer is provided with a spectral analysis means for obtaining the spectrum-related information of transmitted light by performing spectral analysis of transmitted light which is transmitted through a sample S, a storage means 80 for storing the standard spectrum-related information for each grain type and a calibration equation for each grain type, and then a sample type identifying means 90 for determining the grain type of sample according to the spectrum-related information of the sample obtained by a spectral analysis means and the standard spectrum-related information for each grain type. Then, it is also provided with a means 100 for specifying the amount of constituent for specifying the amount of constituent of the sample by selecting the calibration equation of the corresponding grain type is selected based on the identified grain type and then using the spectrum-related information of the sample and the selected calibration equation.