PURPOSE: To facilitate the operation and make the observation high-reliability, by using a static pressure air bearing, which supports a sample table without contacting, and compressed air as a power source for moving the sample table.

CONSTITUTION: A compressed air discharge exit 15 is provided in a prescribed position of a guide part 14, and a sample table 16 is held by discharged compressed air. When the sample table 16 is separated from a driving shaft 18 and compressed air is discharged from a pipe 29, air collides against a driving plate 31, and the sample tabe 16 is moved to a point B.