An ion analyzer 1 includes: an ionization chamber 10; an ionization unit 3 configured to generate ions from a sample 11 in the ionization chamber 10; an analysis chamber 20 separated from the ionization chamber 10 by a partition wall 21 in which an opening 211 is formed; an ion transport unit 22, 23, and 24 provided in the analysis chamber 20 and configured to transport the ions generated in the ionization unit; an ion trapping unit 25 provided in the analysis chamber 20 and configured to trap the ions transported by the ion transport unit 22, 23, and 24; an ion detection unit 26 provided in the analysis chamber 20 and configured to detect the ions released from the ion trapping unit 25; and a single evacuation mechanism 28 connected only to the analysis chamber 20 and configured to evacuate the analysis chamber 20 to a pressure of 103 Pa or less.