Data for a plurality of samples collected by an LC/MS, GC/MS or other systems are converted into a two-dimensional table format without losing information and with a light load, thereby allowing a multivariate analysis processing to be efficiently performed. After LC/MS data on a plurality of samples are obtained and the respective extracted ion chromatograms (XICs) are created (S1 and S2), the correction of the retention-time difference, the waveform processing and the like are performed (S3 and S4), followed by the creation of a one-dimensional table in which the signal-strength values are arranged for each XIC. Then, one-dimensional tables of a plurality of XICs for one sample are joined together in order of m/z value to create an elongate one-dimensional table (S5). The elongate one-dimensional tables of a plurality of samples are arranged in another dimensional direction to obtain a two-dimensional table (S6).