An inspecting apparatus for inspecting a substrate includes an objective lens attaching part equipped with a plurality of objective lenses each having a different working distance (WD), an objective lens exchanging device which exchanges the objective lens, and a loading stage which is opposed to the objective lens and on which the substrate S is loaded. An objective lens detecting device detects the WD of the objective lens. Displacing devices relatively displace the objective lens and the loading stage in the direction of the optical axis of an inspecting light path and a direction rectangular to the optical axis. And a displacement controlling device controls the relative displacement of the objective lens and the loading stage in the direction rectangular to the optical axis when the lens detecting device detects that the WD of the objective lens is shorter than a predetermined WD.