A bimorph type of piezoelectric actuator is used to control the vibration of a thin cantilever beam. The actuator, a bending moment generator, mounted near the clamped end is activated by the strain signal measured from the beam surface under two different situations depending upon the presence of external disturbance. The system transfer function model is experimentally determined by treating the voltage input to the actuator as the input and the strain signal as the output, and then the proper control scheme is designed based on the model to reduce the vibration of the free end of the cantilever. Experimental results show that the integral control action is very effective in increasing the damping of the controlled system.