1. A spectroscopic analysis method comprising: a principal-component analyzing step of calculating, by performing principal component analysis on a collection of optical spectra measured at individual positions of a specimen, principal components of a plurality of orders that constitute the individual optical spectra; a principal-component-image creating step of creating, for the individual orders, principal-component images in which values thereof are principal-component scores of the individual principal components obtained in the principal-component analyzing step, corresponding to the positions; a first identifying step of identifying distribution patterns of the principal-component scores in the individual principal-component images created in the principal-component-image creating step; a second identifying step of identifying the morphology of the specimen in a morphological image in which the specimen is captured; a comparing step of comparing the distribution patterns of the principal-component scores identified in the first identifying step with the morphology of the specimen identified in the second identifying step and of identifying principal-component images that have the distribution patterns correlated with the morphology of the specimen; and a reconstructing step of reconstructing the individual optical spectra by using, among the principal components obtained in the principal-component analyzing step, principal components in which orders thereof correspond to orders of the principal-component images identified in the comparing step.