Ultrasonic probe and method of preparing ultrasonic probe

An ultrasonic probe comprising:

• a first piezoelectric element array in which first piezoelectric elements each as a both-sided electrodes-providing piezoelectric element are two-dimensionally arrayed;
• a second piezoelectric element array layered on the first piezoelectric element array, in which second piezoelectric elements are two-dimensionally arrayed, a first electrode is placed on a second piezoelectric element surface on an opposite side of the first piezoelectric element array, and a second electrode is placed on another second piezoelectric element surface on a side of the first piezoelectric element array,
• an acoustic separation section provided between the first piezoelectric elements to each other, arrayed in the first piezoelectric element array, and
• a signal line comprising a conductive layer coated on an outer circumferential surface of a core material and the core material having an acoustic impedance nearly equal to another acoustic impedance of the acoustic separation section, the signal line connected to the second electrode by passing through the acoustic separation section.