The purpose of this study is to automatically position a workpiece model at an arbitrary point with high precision. For precision positioning with a gripped workpiece model，the diaphragm chuck has a piezoelectric element in each of the three jaws. Despite the disadvantages of narrow-range movement and hysteresis，the piezoelectric element is popular for use in fine adjustment because of the advantages of compactness，high resolution，good responsiveness，and control at an applied voltage. The workpiece model position was measured using a CCD camera. The CCD camera allowed quick position measurement. A voltage was applied to the piezoelectric elements to excite them as actuators for the automatic precision positioning of a workpiece model gripped by the diaphragm chuck with three jaws. Displacement to the target position was set to 7μm for positioning. Consequently，precision positioning with an error of within 0.39μm was realized in any direction.