A piercing needle capable of clear imaging even if an angle to the irradiation direction of a detection wave such as an ultrasonic wave of an ultrasonic probe is small. According to one embodiment, a ultrasonic piercing needle (1) that conducts piercing while observing a piercing condition by means of a ultrasonic image is formed with an edge (13) at the tip end of a piercing needle body (11), and formed at a specified position of the piercing needle body (11) with at least one corner cube mirror (12) formed by a triangular pyramid recess. Since a ultrasonic wave oscillated from the ultrasonic probe is reflected off the corner cube mirror (12) to be returned to the ultrasonic probe, the reflected wave progresses in the same direction as the incident direction of the ultrasonic wave to be positively returned to the probe even when an angle formed by the irradiation route of a ultrasonic wave and the axis of the piercing needle is small.