A driving mechanism relatively displaces a measuring unit and a sample table such that a relative positional relationship between the measuring unit and the sample table is switched between a first positional relationship and a second positional relationship. In the second positional relationship, the sample table is exposed to the outside from within a lower housing. A controller includes a high voltage generation circuit that generates a high voltage to be supplied to a scanner. A first mechanical switch causes a power supply not to supply a voltage to the high voltage generation circuit in the second positional relationship.