ULTRASONIC FLAW DETECTION DEVICE AND ULTRASONIC FLAW DETECTION METHOD

A transducer main body 7 has, on a front end side thereof, an oscillating plane 9 having a bent shape in a side view and corresponding to a larger-diameter curved surface formed at a bend Wc of a laminated part W. Over the oscillating plane 9 of the transducer main body 7, a plurality of piezoelectric oscillators 11 are distributed in a matrix in a bent direction AD and a width direction BD. In each oscillator group 11G, a controlling unit 5 switches the piezoelectric oscillators 11 to transmission and reception piezoelectric oscillators by turns in the width direction BD according to a preset transmission/reception pattern and processes a received signal from the reception piezoelectric oscillator 11 according to an aperture synthesis method.