To obtain information showing the apparatus condition corresponding to measurement result by procession this result after allotting cords to individual apparatus and recognizing as to whether the measurement of the no. of foreign substances is a regular work under a usual control or irregular work, such as experiments.

Whether a regular work under a mormal control or irregular work such as experiments is recognized by a measuring condition storage 202. Based on this, measurement conditions are selected, and the no. of foreign substances is measured by a foreign substance measuring part 204. Based on that result, a measurement result discriminating part 206 generates apparatus condition signals. Accordingly, the possibility of stopping the apparatus for which originally there is no need for stoppage is reduced.