PURPOSE: To avoid creation of dust and facilitate both the identification by mechanical reading and the identification by visual inspection of an operator by a method wherein regular reflection parts which have mirror surfaces and irregular reflection parts which have rough surfaces are formed in a predetermined region on a wafer and a light beam is applied to those parts and the reflected light is measured.

CONSTITUTION: An identification pattern 2 is formed in a predetermined region on a wafer 1 such as an edge part where an orientation flat 1a is formed. The pattern 2 is composed of, for instance, quarrer codes or the like. One quarrer code is composed of four square blocks. A number is stamped in the block. By using the respective blocks as regular reflection parts which have mirror surfaces or irregular reflection parts which have rough surfaces, one code can express numbers 0W15 or 0W16. A laser beam from a laser emitting apparatus is applied to the quarrer codes and the reflected light is measured by a photodetector 11 to read the number expressed by the quarrer code.