First and second actuators where positive electrodes and negative electrodes are disposed on cylindrical electrostrictive polymers are disposed so as to face each other via a fixing member, a blade inserted into the first actuator is provided on the fixing member, and the blade is ultrasonically vibrated via the fixing member by driving one of the first and second actuators in a stretching and shrinking manner and driving the other in a stretching manner in synchronization with each other.
