PURPOSE: To make it possible to change the thickness of a sample by fixing the top face of the sample with the face free and by cutting the top face, through vacuum-sucking the bottom face of the sample or through holding outwardly inclined faces of both sides of the sample by a fixing tool.

CONSTITUTION: A sample 24 is vacuum-sucked and fixed to a sample rest through holes provided on said rest, or the whole bottom surface of the sample 24 is fixed to the rest by providing inclined surfaces, which are held by fixing metals 56, on the outsides of both sides of the sample 24. Thus, it is possible to cut the top face of the sample 24 by means of a grinder, etc. and to cut the thick direction thereof.