INSPECTION DEVICE AND INSPECTION METHOD THEREOF

An inspection device capable of inspecting a foreign matter even during rotation acceleration/deceleration of an object under inspection. The inspection device includes a rotation-and-translation unit configured to rotate and translate the object under inspection; a light intensity modulation unit configured to modulate intensity of laser light to irradiate the object under inspection; a light intensity control unit configured to control the light intensity modulation unit; an object-under-inspection-operation detection unit configured to calculate information about a linear speed at a laser irradiation position on the object under inspection; a data processing unit configured to start foreign matter and defect inspection when a rotation speed of the object under inspection reaches a predetermined speed; and a rotation-and-translation control unit configured to determine a time required for a next single rotation of a rotation stage, and apply, to a translation stage, a translation control value for moving the translation stage.