PURPOSE: To provide a standard sample in which holes having the same size are uniformly distributed by finishing one surface of an A(2 substrate to an almost mirror surface and forming a porous film on the mirror surface by anodic oxidation.

CONSTITUTION: After finishing one surface 11a of an A1 substrate 11 of ≥4N to a mirror surface and cleaning the surface 11a, a porous film 12 is formed on the surface 11a by anodic oxidation. In the film 12, circular holes 13 are arranged adjacent to each other with an oxide film 14 in between. The holes 13 are enlarged and the thickness of the film 14 is adjusted by dipping the substrate 11 in an etching bath. Then the holes 13 are filled with Ni 15 by electrolytic deposition so that the Ni 15 can be protruded from the surface 11a. The surface 16 of the Ni 15 is polished to an almost mirror surface by polishing the protruded surface of the Ni 15 and shaving the film 12 to a prescribed thickness. Then projections 17 are formed by protruding the Ni 15 by selectively etching the film 14. Thus a standard sample on which circular projections 17 which have the same size and are protruded from the surface 18 of the substrate 11 finished to an almost mirror surface at a uniform height are distributed and the protruded surfaces of the projections 17 are nearly arranged in a plane.