Behind an electronic circuit, a thermally anisotropic main backing is provided. The main backing has two outer surfaces (low thermal conductivity surfaces) perpendicular to an X direction. In a first gap located adjacent to one of the outer surfaces, an FPC and a first group of electric components are arranged. In a second gap located adjacent to the other one of the outer surfaces, the FPC and a second group of electric components are arranged.

An ultrasonic probe includes: a piezoelectric element; and a backing material including a matrix resin and thermally conductive particles, arranged on one direction side with respect to the piezoelectric element, wherein a ratio of thermal conductivity of the backing material in a thickness direction to the thermal conductivity of the backing material in a horizontal direction is 3 or more.