During normal and reverse swings of a transducer main body, an engagement accuracy is ensured to reduce generation of vibration and noise. An ultrasonic transducer includes: a coupling swingably and loosely fitted between one end portion of an output shaft of a power source that swings the transducer main body and the transducer main body, and a flywheel swingably and loosely fitted to another end portion of an output shaft of the power source, ensuring the reduced vibration and noise from the transducer main body.
