1. A data processing device configured to process measurement spectral data by using a multivariate analysis, the data processing device comprising: a determination unit configured to, based on the measurement spectral data, determine sampling intervals to be used in the multivariate analysis; a data group obtaining unit configured to obtain a spectral data group of the sampling intervals determined by the determination unit; and a multivariate analysis unit configured to carry out the multivariate analysis by using the spectral data group obtained by the data group obtaining unit, wherein the determination unit determines the sampling intervals based on one of a rate of change of a spectral distribution, intensity information in a frequency space, a magnitude of a spectral intensity distribution, or a magnitude of a Mahalanobis distance.