A charged particle beam instrument is offered which can introduce cooled samples easily into a sample chamber. The charged particle beam instrument (100) of the present invention has: a sample container (10) that accommodates samples (S) and a refrigerant (6) for cooling the samples (S); an evacuated sample chamber (20); a sample exchange chamber (30) connected with the sample chamber (20); a partition valve (40) disposed between the sample exchange chamber (30) and the sample container (10); and vacuum pumping equipment (50) for evacuating the sample container (10). The sample container (10) can be connected with the sample exchange chamber (30) via the partition valve (40). The sample container (10) is evacuated by the vacuum pumping equipment (50) while the partition valve (40) is closed.