Provided is a wave motion analysis device 100 that detects a defect in a body being scanned on the basis of reflected waves obtained from the body being scanned, the wave motion analysis device 100 comprising: a multiple-reflection region extraction unit 106 that acquires fault data generated on the basis of the reflected waves, and that extracts, from the fault data, a multiple-reflection region in which it is possible to mainly detect multiple-reflection signals in accordance with a depth range deeper than the depth at which an actual image of the body being scanned can actually be detected in the fault data; and a detection unit 107 that detects, from the extracted multiple-reflection region, a multiple-reflection image corresponding to a defect in the body being scanned.