PURPOSE: To easily obtain a sample including a purposive section suitable for a high-magnification observation without relying on a skill degree by a method wherein the region of an active layer on the surface on one side of a semiconductor wafer is detected by the means of a magnifier, a notch is formed in the wafer in such a way that no notch is formed in the active layer and the vicinity of the active layer is pressed.

CONSTITUTION: A positioning of a magnifier is performed by visual observation and a semiconductor wafer 1 is fixed on a table 6. The semiconductor wafer 1 is fixed in such a way that the surface, on which an active layer 2 is not formed, is turned to a diamond blade 8. Then, the active layer 2 is detected using the magnifier and the table 6 is moved in such a way that the region of the active layer 2 and a positioning mark 71 coincide with each other. Then, the table 6 is lowered in the direction of G while the diamond blade 8 is made to rotate and made to move reciprocally in the directions of A and B with the region of the active layer 2 as the reference. After a preset notch is formed in the semiconductor wafer 1, the vicinity of the active layer 2 is pressed by a diamond cutter. Whereupon, the wafer is divided and a sample having a section to observe can be easily made.