Defect inspection apparatus and defect inspection method

A defect inspection apparatus comprising:

• an exciter configured to impart elastic wave vibration to an inspection target to excite the elastic wave vibration in the inspection target;
• an irradiator configured to irradiate the inspection target in an excited state in which the elastic wave vibration is excited by the exciter with laser light;
• and
• a measurer configured to change a phase of the laser light reflected by the inspection target to cause the laser light having an unchanged phase to interfere with the laser light having a changed phase, and to measure interference light, wherein
• the measurer is configured to acquire, based on interference light of the laser light with which the inspection target is irradiated by the irradiator and that passes through a first light path in which the reflected laser light travels from the inspection target toward the measurer, an interference image representing a vibration state of the inspection target as viewed in a direction extending along the first light path, and to acquire, based on interference light of the laser light with which the inspection target is irradiated by the irradiator and that passes through a second light path in which the reflected laser light travels from the inspection target in a direction different from the first light path, an interference image representing a vibration state of the inspection target as viewed in a direction extending along the second light path.