An ultrasonic probe includes a substrate, a diaphragm, a thin-film piezoelectric element, a communication passage, and an air hole. The substrate has first and second cavities thereon. The diaphragm is configured at the first cavity. The thin-film piezoelectric element is configured to the diaphragms. The communicating passage is configured in the substrate and extending from the first cavity to the second cavity. The air hole extends between the communicating passage to an outside of the substrate.
