Provided are an ultrasonic testing probe and an ultrasonic testing apparatus capable of reducing the time required for flaw detection while maintaining the flaw-detection capability, irrespective of the shape of the inner surface of a tested object. The respective rib edges are joined to form a corner rib defining an angle. A shroud is pivotally mounted to the support for movement between an operative position overlying the tubular outlet to prevent access to cam lock coupling ears and an inoperative position spaced from the tubular outlet. A first width of the first kerf is larger than a second width of the second kerf. In an alternate embodiment, the crossfire tubes also contain a plurality of air purge holes that provide a layer of cooling air along the crossfire tube inner wall.