Patent ID: 8490490

Claim:
An ultrasonic testing method comprising the steps of: arranging an ultrasonic probe having a plurality of transducers so as to face a tubular test object, and causing transducers appropriately selected from said plurality of transducers to transmit and receive ultrasonic waves so that the ultrasonic waves are propagated in said tubular test object in a plurality of propagation directions that have different propagation angles from each other, wherein an ultrasonic testing condition by said ultrasonic probe is set so that respective external refraction angles θr of the ultrasonic wave in said plurality of propagation directions are approximately equivalent and/or respective internal refraction angles θk of the ultrasonic wave in said plurality of propagation directions are approximately equivalent, wherein said propagation angle is defined as an angle formed by the propagation direction, which is a propagation direction viewed from the normal direction of the tangential plane of the tubular test object including the incident point of the ultrasonic wave, of the ultrasonic wave having entered the tubular test object and a circumferential tangent of the tubular test object passing through the incident point.