To reduce vibration of a blade.

Plural lamination type piezoelectric actuators 2 are embedded in both an upper and a lower surface of a blade 1 of a helicopter, and piezoelectric sensors 3 to measure vibration of the blade 1 are embedded between the lamination type piezoelectric actuators 2 and at end parts of them. Signals measured by the piezoelectric sensors 3 are transmitted to a controller 4. The controller 4 controls a power source 5 as a voltage supply source to the lamination type piezoelectric actuators 2 based on the transmitted signals, and it gives vibration of the opposite phase to measured vibration of the blade 1.