Provided are: an ultrasonic probe (1) for a puncture needle that transmits ultrasonic waves from a transducer array (2), which is disposed at a predetermined array inclination angle (0) with respect to a subject contact face (S2), to a subject (P) in a direction in which an angle of an ultrasonic transmission/reception face (S1) with respect to a direction of puncture of the puncture needle (N) punctured toward the front of the subject contact face (S2) from a puncture position (I) becomes smaller, receives ultrasonic echoes, forms an acoustic ray signal (La) inclined toward the puncture needle (N), and generates a B mode image of a depth of the subject (P) from the acoustic ray signal (La); and an ultrasonic diagnostic device including the same.