An analytical device includes: a mass spectrometry unit that separates ions based on flight time and detects the ions having been separated; an analysis unit that creates data corresponding to a spectrum in which an intensity of the ions having been detected and the flight time or m/z corresponding to the flight time are associated; a peak width calculation unit that calculates a first peak width at a first intensity and a second peak width at a second intensity different from the first intensity for at least one peak in the spectrum; and an adjustment unit that performs an adjustment of the mass spectrometry unit based on the first peak width and the second peak width.