Ultrasonic inspection apparatus and method

An ultrasonic inspection apparatus comprising:

• a first ultrasonic probe that is disposed on an outer surface of an inspection object, and transmits an ultrasonic wave to an inside of the inspection object;
• a second ultrasonic probe that is disposed on the outer surface of the inspection object so as to be separated from the first ultrasonic probe, and receives the ultrasonic wave reflected by an inner surface of the inspection object;
• a control device that is configured to output a pulse signal for making the first ultrasonic probe transmit the ultrasonic wave to the first ultrasonic probe, that is supplied with a waveform signal obtained by converting the received ultrasonic wave from the second ultrasonic probe, and that is configured to compute a thickness reduction depth of the inspection object between the first ultrasonic probe and the second ultrasonic probe;
• and
• a display device that displays the thickness reduction depth of the inspection object computed by the control device, wherein
• the control device is configured to
• compute the thickness reduction depth of the inspection object between the first ultrasonic probe and the second ultrasonic probe by selectively using a reception time of the ultrasonic wave transmitted from the first ultrasonic probe, reflected once by the inner surface of the inspection object, and received by the second ultrasonic probe, and a reception time of the ultrasonic wave transmitted from the first ultrasonic probe, reflected twice by the inner surface of the inspection object, and received by the second ultrasonic probe.