A chromatograph mass spectrometer includes: a chromatograph unit configured to separate components in a sample; a mass spectrometer configured to perform measurement on ions having a specific mass-to-charge ratio derived from each compound temporally separated by the chromatograph unit, an analysis condition setting unit configured to allow a user to set, as an analysis condition, molecular-weight-related information and a mass-spectrometry-related parameter including an ion polarity, a type of an adduct, a number of polymerizations of a multimer and/or an ion valence for each measurement target compound; and an analysis method creator configured to calculate a mass-to-charge ratio of one or a plurality of types of ions according to the analysis condition set by the analysis condition setting unit for the each measurement target compound, and create an analysis method for performing mass spectrometry on the one or a plurality of types of ions in a time division manner.