The present invention application provides a bathtub. On the bathtub wall are fixed ultrasonic transmitters, and an ultrasonic transducer drive circuit is electrically connected to ultrasonic transducers. The ultrasonic transmitters further include an ultrasonic divergent structure which, after reflecting and scattering the ultrasonic waves emitted by the ultrasonic transducers, transmits the same into the bathtub (e.g., into the water of the tub).