A body-cavity-insertion-type probe wherein an internal unit (internal assembly) has an oscillator unit, a relay board, and electronic circuit board, and a backing member. The backing member is retained in a state of being housed inside a backing case, and the backing case is retained by two recesses formed in an inside surface of a heat dissipation shell as a probe head case. An exhaust heat sheet is joined to a peripheral region of a back surface of the electronic circuit board. A rear wing and a front wing of the exhaust heat sheet are joined to the backing case.
