The invention provides an ultrasonic probe where a longitudinal axis and a transverse axis are recognized with a probe matched with the shape of the hand and the longitudinal axis and the transverse axis are switched by rotating the probe according to use. In the ultrasonic probe 102 for transmitting and receiving ultrasonic waves, a narrowed part 204 with a rectangular cross section is formed at a part close to the oscillator array part 201 of a case of the probe, and a round part with a circular cross section is formed at a part connected with the narrowed part 204 and close to a cable pull-out part.