PURPOSE: To reduce a total inspection time without using image data by an image pick-up device and at the same time prevent dependency on the surface state of a target to be inspected.

CONSTITUTION: Processed light is applied from above obliquely to the surface position of a drive table 3 which is provided vertically below an image pick-up device 4 and then the reflection position of the processed light on the drive table 3 is detected by a reflection position detector 5 when the drive table 3 mounting an object 8 to be inspected is moved. The reflection position of the processed light at the focusing position of the image pick-up device 4 is stored in advance, the reflection position of the reflection position detector 5 generated when moving the drive table 3 is compared with the reflection position in the focusing position, and then the traveling of the drive table 3 is stopped when the agreement of both is detected.