A technique that can make a heat radiation effect higher and makes even a transmission voltage of an ultrasonic diagnostic apparatus higher and then makes a diagnostic depth deeper is disclosed. According to this technique, an ultrasonic probe has: a plurality of piezoelectric elements 1 which are long in an X-direction, are arrayed in a y-direction and transmit and receive ultrasonic waves in a z-direction (diagnostic depth direction); a plurality of ground electrodes 2 and signal electrodes 3 which are placed on the front surfaces and the rear surfaces of the individual piezoelectric elements, respectively; a plurality of signal electrodes 4 for extracting respective signals from the individual signal electrodes; a backing load member 5 which has a function for mechanically holding the piezoelectric elements through the signal electrodes and attenuating the unnecessary ultrasonic signal as necessary; a plurality of sheet-shaped heat conduction members 6 which are embedded inside the backing load member and positively transmit the heat generated from the piezoelectric elements; and a heat radiating block 7 which is linked to the heat conduction members on the rear side of the backing load member and radiates the heat transmitted through the heat conduction members.