Provided is an ultrasonic probe including: a cMUT chip having a plurality of vibration elements whose electromechanical coupling coefficient or sensitivity is changed according to a bias voltage and transmitting and receiving ultrasonic waves； an acoustic lens above the cMUT chip； and a backing layer arranged below the cMUT chip. Electric leakage preventing means is provided at the ultrasonic wave transmitting/receiving surface side of the acoustic lens or between the acoustic lens and the cMUT chip. The electric leakage preventing means is, for example, an insulating layer such as a ground layer. By using such a structure, it is possible to provide an ultrasonic probe capable of preventing electric leakage from the ultrasonic probe to an object to be examined so as to improve the electric safety and an ultrasonic diagnostic apparatus using the probe.
