PROBLEM TO BE SOLVED: To improve an apparatus throughput by suppressing vibration according to speeding up of a sample stage, and allowing to stably obtain an image in a reaction state of an observation sample with a reagent in a DNA sequencer. SOLUTION: There is provided the DNA sequencer using a stage mechanism including: a feed screw; a nut screwed with the feed screw; a fed member mounted on the nut; a rotation driving means for rotating the feed screw; a coupling with a torsional rigidity variable mechanism for connecting the rotation driving means to the feed screw; and a means for controlling the rotation driving means and coupling with the torsional rigidity variable mechanism. COPYRIGHT: (C)2012,JPO&INPIT
