This paper presents a vibration suppression approach for a galvanometric mirror in laser positioning devices. In the system, it is important to achieve a fast and high-precision positioning of the mirror by a motor. In addition, it is indispensable to maintain flatness of the mirror after position settling. However, since natural vibration frequencies of the mirror are excited by the force of moment generated during positioning, and corresponding residual vibration occurs, it is difficult to maintain the flatness of the mirror. In this paper, therefore, the vibration is directly suppressed by mounting a piezoelectric element on the mirror, where the function of both sensor and actuator of the piezoelectric element is simultaneously used. The proposed approach has been verified by experiments using a positioning device for industrial galvano scanners.