PURPOSE: To enable a sample to be accurately and smoothly shifted even at high magnification while minimizing friction on a slide surface by making variable the pressing force of a spherical body acting on a recessed spherical surface.
CONSTITUTION: The turning of a fine adjustment knob 17 causes the shift of a sample stage 4 along a guide 13. As a result, the sample stage 4 yaws about a spherical body 7 as a support point, thereby causing the shift of a sample introduction rod 5 accommodated in the spherical body 7 and a sample 12 placed thereon. The aforesaid yawing motion occurs via the slide of a recessed spherical surface 8 and the spherical body 7 along the contact surface thereof and, therefore, motion with less friction and high smoothness can be obtained. In this case, a presser spring 10 is used to apply a force on a slide surface in the same or opposite direction to atmospheric pressure for turning a spring seat 11, thereby making a pressing force variable. According to the aforesaid construction, a precise shift amount can be transmitted to the sample 12, when friction on the slide surface becomes minimum, and the sample 12 gives a regular motion.