The invention relates to a minor axis motion type ultrasonic probe with high sensitivity that suppresses propagation loss. The minor axis motion type ultrasonic probe of the invention comprises: a piezoelectric element group in which a plurality of piezoelectric elements are arranged in a line in a major axis direction of the piezoelectric element group an acoustic lens that is provided on an ultrasonic wave transmitting/receiving surface side of the piezoelectric element group and that has a predetermined curvature in a minor axis direction of the piezoelectric element group and a sealed container that houses the piezoelectric element group with the acoustic lens provided thereon and that is filled with a liquid serving as an ultrasonic wave medium, and the piezoelectric element group is moved in the minor axis direction and ultrasonic waves are transmitted and received to and from a living body, wherein the configuration is such that the acoustic lens is a concave lens formed from a material that has less propagation loss than a silicone resin and that has a greater acoustic velocity than a living body, and a relationship between acoustic velocity c1 of the concave lens, acoustic velocity c2 of the liquid, and acoustic velocity c3 of the living body is expressed as c1>c3>c2.
