An irradiation unit configured to scan and irradiate a sample with pulse waves; a reception unit configured to receive reflected waves of the pulse waves from the sample; a waveform generation unit configured to generate time waveforms of a signal representing the reflected waves at respective scan positions of the pulse waves; and a waveform correction unit configured to detect at least one peak in each of the time waveforms, and correct each of the time waveforms on a basis of each of positions of the at least one peak in the time waveforms are included.