An ultrasonic probe suitable for reducing reflected waves returning from a rear surface part to a transducer side, and an ultrasonic diagnostic apparatus. Ultrasonic probe 1 comprises transducer 10 transmitting and receiving ultrasonic waves to and from a subject, a backing material 12 disposed on the rear side of the transducer 10, and heat dissipating block 14 stacked on the backside of the backing material 12. At least one of the backing material 12 and heat-dissipating block 14 comprises void 16 therein. A sound absorbing material 18 is desirably filled in void 16.
