INSPECTING DEVICE

PROBLEM TO BE SOLVED: To properly attain inspection of a microfine pattern by maintaining an environment in which inspection of a semiconductor wafer or the like is operated in a high clean level. SOLUTION: A device main body 10 for inspecting a semiconductor wafer or the like is housed inside a clean box 3, and clear air is supplied from the clean box 4 to the inside part of the clean box 3 in which the device main body 10 is housed. The clean air unit 4 is provided with a plurality of air blowers 5a and 5b, and the air volume of clean air to be supplied to the inside part of the clean box 3 is controlled. The air volume is initialized so that a positive pressure state and an air speed optimal for inspection can be set. In a normal operation, the air speed set in the initializing state is varied according to the internal-and-external air pressure difference of the clean box 3.