Inspection device, inspection facility and inspection device failure confirmation method

An inspection device failure confirmation method in which a failure of an inspection device is confirmed, the inspection device detecting whether or not there is a foreign matter or dirt adhered to a surface of a workpiece or whether or not there is a scratch on the surface of the workpiece, wherein:

• the inspection device includes a mounting part on which the workpiece is mounted, a light source part that irradiates the surface of the workpiece, and a cover part that covers the mounting part and the light source part and blocks light coming from an outside light source from entering the inspection device, the outside light source being positioned outside the inspection device;
• a first polarizing plate having a polarizing axis in a first direction is attached to an open window provided in the cover part, and a second polarizing plate having a polarizing axis in a second direction orthogonal to the first direction is attached to the open window so as to be able to open and close;
• the inspection device failure confirmation method, comprising:
• installing the outside light source and the inspection device so that the second polarizing plate overlaps the first polarizing plate in a state where the second polarizing plate is closed, and the first polarizing plate and the second polarizing plate are present on a straight line that connects the outside light source and the workpiece in the state where the second polarizing plate is open;
• and
• inspecting an inside of the inspection device visually through the first polarizing plate in the state where the second polarizing plate is open so that it is able to confirm whether or not there is a failure in the inspection device.