<p>An ultrasonic probe (1) includes a plurality of piezoelectric elements (2A-2F) extending concentrically. The elements have respective surfaces via which ultrasonic wave is transmitted and received. The surfaces of the elements (2A-2F) are concave and have predetermined radii of curvature (ra-rf) respectively. The radii of curvature increase as the elements are farther from an innermost place and closer to an outermost place.</p>
