Foreign substance detection device and foreign substance detection method

Abstract

A foreign substance detection device configured to detect a foreign substance contained in a processing liquid configured to process a substrate includes multiple processing liquid flow path forming mechanisms configured to form multiple processing liquid flow paths through which the processing liquid to be supplied to the substrate flows; a radiator configured to radiate radiation light from a light source toward each of the multiple processing liquid flow paths; and a light receiver configured to receive light emitted from the processing liquid flow paths by radiating the radiation light. The radiator includes a light adjuster configured to adjust a light amount of the radiation light radiated to the multiple processing liquid flow paths.

Dependencies are inferred from the claim text.