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.