A chromatograph mass spectrometer having a chromatograph section in which sample components having one or more compounds are separated in a temporal direction and a mass spectrometer section in which the sample components are sequentially subjected to a mass analysis, the mass spectrometer section being capable of selectively performing (i) a scan measurement in which a mass-to-charge ratio is continuously and repeatedly scanned over a predetermined mass range, (ii) a selected ion monitoring measurement in which the mass-to-charge ratio is switched from one value to another in a stepwise manner, with each value maintained for a specific period of time, or (iii) a simultaneous scan/SIM measurement in which the SIM measurement is performed during the scan measurement, which Is characterized by: a) a display controller showing a previously-created compound table on a screen of a display unit, the compound table including a list showing the kind of each compound, a normal retention time of each compound, and one or more mass-to-charge ratios characteristic of each compound; b) a selector for allowing an operator to select one or more compounds that should undergo the simultaneous scan/SIM measurement, from the compound table displayed on the screen; and c) a measurement condition table creator for producing a measurement condition table, wherein the chromatograph mass spectrometer is configured to perform a measurement according to the measurement condition table and wherein the measurement condition table creator includes: means for determining the retention time of each selected compound, means for automatically setting a measurement time range for each selected compound by determining a time span before and after the retention time of each selected compound, and means for assigning the simultaneous scan/SIM measurement to the measurement time range for each selected compound and for assigning either the scan measurement or the SIM measurement to other measurement time ranges. a) a display controller showing a previously-created compound table on a screen of a display unit, the compound table including a list showing the kind of each compound, a normal retention time of each compound, and one or more mass-to-charge ratios characteristic of each compound; b) a selector for allowing an operator to select one or more compounds that should undergo the simultaneous scan/SIM measurement, from the compound table displayed on the screen; and c) a measurement condition table creator for producing a measurement condition table, wherein the chromatograph mass spectrometer is configured to perform a measurement according to the measurement condition table and wherein the measurement condition table creator includes: means for determining the retention time of each selected compound, means for automatically setting a measurement time range for each selected compound by determining a time span before and after the retention time of each selected compound, and means for assigning the simultaneous scan/SIM measurement to the measurement time range for each selected compound and for assigning either the scan measurement or the SIM measurement to other measurement time ranges. means for determining the retention time of each selected compound, means for automatically setting a measurement time range for each selected compound by determining a time span before and after the retention time of each selected compound, and means for assigning the simultaneous scan/SIM measurement to the measurement time range for each selected compound and for assigning either the scan measurement or the SIM measurement to other measurement time ranges.