An antibody analysis system composed of a measuring apparatus that is configured to measure Raman spectroscopy spectra and an antibody analyzer, the antibody analyzer comprising: an actual measured data storage section that is configured to store in pairs a plurality of actual measured Raman spectroscopy spectra obtained through measurement of a sample of an antibody drug containing an antibody, under a plurality of different external stimulus conditions, by the measuring apparatus, the conditions being either one of a concentration or a pH of a solute added to the sample, an existence time of the sample in a gas-liquid interface or a solid-liquid interface, or a temperature, and the external stimulus conditions under which the actual measured Raman spectroscopy spectra are respectively measured; an evaluation criterion vector setting section that is configured to set an evaluation criterion vector having a number of elements equal to a number of measurement points for a wavenumber at which spectrum intensity of the actual measured Raman spectroscopy spectra is measured; a score calculation section that is configured to calculate a score based on an inner product of the actual measured Raman spectroscopy spectra and the evaluation criterion vector with respect to the external stimulus conditions; and a change feature point determination section that is configured to determine a change feature point of the antibody on a basis of a change in the score with respect to the external stimulus conditions, wherein the evaluation criterion vector setting section is configured to set the evaluation criterion vector by calculating one or a plurality of PCA loadings on a basis of a spectral matrix composed of the plurality of actual measured Raman spectroscopy spectra measured under the plurality of external stimulus conditions, and the score calculation section is configured to calculate a product of the spectral matrix and each of the PCA loading as the score under the external stimulus conditions, and wherein the evaluation criterion vector setting section is configured to set the evaluation criterion vector by calculating the PCA loadings having at least second and third contribution rates, and the change feature point determination section is configured to determine a change feature point due to a minute structural change in an early stage of denaturation that occurs in the antibody on a basis of a change in the score corresponding to the PCA loadings having at least second and third contribution rates calculated by the score calculation section, with respect to the external stimulus conditions. an actual measured data storage section that is configured to store in pairs a plurality of actual measured Raman spectroscopy spectra obtained through measurement of a sample of an antibody drug containing an antibody, under a plurality of different external stimulus conditions, by the measuring apparatus, the conditions being either one of a concentration or a pH of a solute added to the sample, an existence time of the sample in a gas-liquid interface or a solid-liquid interface, or a temperature, and the external stimulus conditions under which the actual measured Raman spectroscopy spectra are respectively measured; an evaluation criterion vector setting section that is configured to set an evaluation criterion vector having a number of elements equal to a number of measurement points for a wavenumber at which spectrum intensity of the actual measured Raman spectroscopy spectra is measured; a score calculation section that is configured to calculate a score based on an inner product of the actual measured Raman spectroscopy spectra and the evaluation criterion vector with respect to the external stimulus conditions; and a change feature point determination section that is configured to determine a change feature point of the antibody on a basis of a change in the score with respect to the external stimulus conditions, wherein the evaluation criterion vector setting section is configured to set the evaluation criterion vector by calculating one or a plurality of PCA loadings on a basis of a spectral matrix composed of the plurality of actual measured Raman spectroscopy spectra measured under the plurality of external stimulus conditions, and the score calculation section is configured to calculate a product of the spectral matrix and each of the PCA loading as the score under the external stimulus conditions, and wherein the evaluation criterion vector setting section is configured to set the evaluation criterion vector by calculating the PCA loadings having at least second and third contribution rates, and the change feature point determination section is configured to determine a change feature point due to a minute structural change in an early stage of denaturation that occurs in the antibody on a basis of a change in the score corresponding to the PCA loadings having at least second and third contribution rates calculated by the score calculation section, with respect to the external stimulus conditions.