PURPOSE: To analyze a specified minute region of several μm or less in a super LSI with a transmission electron microscope by forming a groove beforehand with a focused ion beam along or in the vicinity of the specified part of a sample.

CONSTITUTION: A recess 2 in a rectangular parallelopiped shape is formed with an ion beam which is focused to 1μm or less along a minute region 1 in a sample to be analyzed A. The sample A is bonded by the same method as a sample for an ordinary transmission electron microscope. Thus a sample block is prepared. Then, the sample block is cut so as to includes the region 1 and the recess 2. The cut piece of the sample is polished to the part where the recess 2 disappears in the direction a - a'. Polishing is further performed from the direction b - b' by the same way, and the thin sample piece is prepared. Thus, the analysis of the specified part having the size of several μm or less can be performed with the transmission electron microscope.