A mass spectrometer capable of analyzing a wide mass range with high sensitivity and high mass accuracy. A mass spectrometer has an ionization source generating ions; an ion transfer optics transferring the ions; a first linear trap accumulating the ions and ejecting the ions in the specific mass range; a second linear trap having an end electrode disposed at the exit end ejecting the ions to change a DC potential gradient relative to a DC potential of the end electrode and trapping the ions ejected from the first linear trap to repeatedly eject them in pulse form; a time-of-flight mass spectrometer accelerating the ions ejected from the second linear trap in the orthogonal direction to detect them; and a controller changing the time duration of the ions in which the ions are ejected from the second linear trap or delay time from the completion of ejection to application of an accelerating voltage of the time-of-flight mass spectrometer according to the mass range of the ions ejected from the first linear trap to the second linear trap.