A product ion spectrum is created on the basis of MS2 analysis data respectively obtained for a parent compound and a metabolite (S1 and S2). Additionally, a neutral loss spectrum, in which the mass of each product ion is replaced with a mass difference between the mass of the product ion and that of a precursor ion, is created (S3). Then, a common peak having the same mass in both the parent compound and the metabolite is extracted (S4), and a complementary peak appearing at a position corresponding to the difference between the mass of the common peak and that of the precursor ion is extracted (S5); the complementary peak corresponding to a common peak located on the product ion spectrum appears on the neutral loss spectrum, while the complementary peak corresponding to a common peak located on the neutral loss spectrum appears on the product ion spectrum. In the process of displaying the four spectrums in an integrated form, different display colors are assigned to the common peak, complementary peak and other peaks so that the different peaks can be easily distinguished (S6 to S9).