The purpose of this research is the reduction of relative motion between two locations of main functional part of precision device under various conditions. First, sensitivity analysis is described which takes only one location, relative motion or objective frequency band into consideration in conventional method. Next, new sensitivity analysis is proposed to consider not only objective frequency band but also relative motion. The new method is applied for a simple numerical model and experimental model, and structural modification is carried out for the reduction of relative motion to compare of conventional methods. Moreover, relative motion between objective lens and stage that are main functional part in microscope for inspection of large scale integration circuit is analyzed by new sensitivity method for reducing relative motion in low frequency band. The image deflection can be reduced by structural modification and evaluated using two dimensional position sensor quantitatively.