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 outlines of 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 an outline of morphology of the specimen in a morphological image in which the specimen is captured; a comparing step of comparing the outlines of distribution patterns of the principal-component scores identified in the first identifying step with the outline of the morphology of the specimen identified in the second identifying step and of identifying one or more of the principal-component images that have the outlines of distribution patterns correlated with the outline of morphology of the specimen; and a reconstructing step of reconstructing the individual optical spectra by: adding one or more of the principal components in which orders thereof correspond to orders of the one or more of the principal-component images identified in the comparing step and correlated with the outline of morphology of the specimen; and removing, from the individual optical spectra, rest of the principal components other than the one or more of the principal components.