ULTRASONIC MEASURING METHOD AND ULTRASONIC MEASURING APPARATUS

PROBLEM TO BE SOLVED: To provide an ultrasonic measuring method and an ultrasonic measuring apparatus which are capable of accurately measuring an object to be measured of which inside diameter is small in a noncontact manner.SOLUTION: An ultrasonic measuring apparatus 1 comprises: an ultrasonic generator 2; a reflecting mirror 4 for deflecting an ultrasonic beam 3 in a direction perpendicular; a measurement probe 5 composed of the ultrasonic generator 2 and the reflecting mirror 4; a vertical mechanism 7 for vertically moving the measurement probe 5; a turntable 10 which is provided on a pedestal 8 and rotates a cylindrical object 9 to be measured; a transceiver 11 which transmits a transmission signal to the ultrasonic generator 2 and receives a reception signal of the reflected ultrasonic beam 3; and a signal processing device 12 for controlling the transceiver 11 and analyzing the reception signal. Thus, the ultrasonic measuring apparatus can accurately measure an object to be measured of which inside diameter is small.