A display area 60 of a display unit of a mass spectrometer shows a result of tuning. The display area 60 includes: a tuning-item displaying section 62 configured to display all tuning items and a result of whether each tuning item has been tuned; and an analyzable-condition displaying section 63 configured to display a condition under which an analysis is possible based on the result. The tuning items may be displayed respectively and individually. Alternatively, the tuning items may be displayed in a grouped manner with a plurality of tuning items in a group. Consequently, a user knows, at a glance, whether the tuning necessary for an analysis that the user intends to perform has been performed. If a necessary tuning item has not been tuned, the user immediately starts to tune (only) the tuning item. Further, a user immediately knows in a current state of tuning whether the analysis that the user intends to perform is possible. Therefore, when the analysis is possible, the user can start the analysis. When the analysis is impossible, the user can tune only the tuning item that has not been tuned and is displayed on the tuning-item displaying section 62.