A ultrasonic probe has a plurality of piezoelectric transducers arranged in the array direction. Each piezoelectric transducer has a piezoelectric element which vibrates in the thickness direction. A signal electrode is formed on the lower surface of the piezoelectric element. An earth electrode is formed on the upper surface of the piezoelectric element. Inside the piezoelectric element, a plurality of non-piezoelectric elements are arranged along the lens direction. Each non-piezoelectric element does not come in contact with the signal electrode and the earth electrode.