The mass analyzing apparatus of the present invention can achieve the speed-up and simplification of the formation of a calibration curve for quantifying an analysis object in a mass analyzing apparatus. The mass analyzing apparatus is provided with: a sample storage-dilution unit 1 for storing samples of the analysis object including a quantitative calibrator in which, with respect to one analysis object to be quantified, two or more kinds of compounds selected from the analysis object, a plurality of stable isotope compounds of the analysis object and a plurality of analogue compounds of the analysis object are mixed at respectively different concentrations; an ionizing unit 5 for ionizing a sample; a mass analyzing unit 6 for analyzing the ionized sample; and a data processing unit 7 in which, based on results of analysis of the quantitative calibrator carried out by the mass analyzing unit 6, two or more concentrations are measured, and the analysis object is quantified based on information of the measurement.