In a mass production line of a semiconductor manufacturing process, foreign particle inspection method and apparatus for preventing occurrence of large quantities of defects and for keeping a necessary yield. The inspection apparatus is made up in a small-sized apparatus and disposed at inlet/outlet of processing apparatuses of the production line or to a transfer system between the processing apparatuses. The inspection apparatus includes at least one monitor for real-time sampling foreign particles possible deposited on wafer which is being carried by the transfer system, thereby enabling simplification in construction of the production line and reduction of manufacturing cost. The inspection apparatus may comprise a refractive index changeable type lens array, a spatial filter and a pattern data elimination circuit, and makes possible to conduct foreign particle inspection on repetitively-patterned portions of the wafers during transfer. With the spatial filter for eliminating repetitive data of the repetition patterns the small-sized compact inspection apparatus is capable of real-time inspecting the foreign particles on the wafers at a high speed.