It is an object of the present invention to provide a mapping-data analyzing method that can display a map in which sufficient information is extracted from the spectra of obtained mapping data to enable objective analysis. The mapping-data analyzing method of the present invention is used for analyzing mapping data obtained by measuring, with a spectrometer apparatus, spectra at a plurality of points on a specimen surface. The method comprises a principal-component calculating step and a grouped-map display step. In the principal-component calculating step, spectral data obtained at each point on the specimen surface is defined as an individual sample and principal component analysis, in which values at a plurality of wave numbers of each spectral data set serve as variables, is performed to calculate the scores of a plurality of principal components for each individual sample. In the grouped-map display step, the points on the specimen surface are divided into a plurality of groups based on the scores of a plurality of principal components calculated in the principal-component calculating step and a two-dimensional or three-dimensional map indicating to which group each point on the specimen surface belongs is displayed on a display device.