Electronics technology has made remarkable progress in recent years, and in the field of automobile noise and vibration control, it has attracted the interest of engineers due to its potential for use in the active control of vibration isolators.This report describes an investigation on reducing automobile vibration caused by engine explosion using a piezo actuator(PA) engine mount. Piezo actuator has a very high speed response but the displacement is generally very small. Therefore PA mount requires an amplitude enlargement mechanism. Here, an active mount with an enlargement mechanism incorporated was developed. For the control system, the adaptive control algorithm proposed by S. J. Elliott et al. was employed as a base, and a control rule against limitation in the power of the actuator was used in combination with it. A significant attenuation of the vibration of the dominant harmonic order in idling was achieved. The results are reported in the following pages.