Abstract: A short axis scanning type ultrasonic wave probe configured such that: a plurality of strip shaped piezoelectric elements is arranged in a long axis direction, which is a crosswise direction of the piezoelectric elements, so as to form a flat piezoelectric element group; the piezoelectric element group is housed within a sealed container filled with a liquid that functions as an ultrasonic wave medium; and the piezoelectric element group is mechanically scanned in a short axis direction, which is a lengthwise direction of the piezoelectric elements, and the piezoelectric element group is linearly moved in the short axis direction so as to be mechanically scanned. Thereby, there is provided a short axis mechanical scanning probe in which the ultrasonic wave transmitting and receiving surface thereof can be easily brought into contact with a protruding section (such as a breast) of a subject human body, while realizing excellent lateral resolution.