To make a surface analysis at high sensitivity by cutting the unnecessary part of a sample in the neighborhood of a specific part and then starting an excavation process from a cut section with a converged ion beam for exposing the specific part.

A sample 2 is cut with a dicing saw or the like in the neighborhood of a specific part 1, or so as to keep a distance L at 10μm or less from the specific part 1 to a cut section 4. A excavation process is then started from the end of the cut section 4, using a converged ion beam (FIB) 6, and an unnecessary part around the specific part 1 is removed. Finally, the cross section 3 of the specific part 1 is exposed and a surface analysis sample 2 is thereby prepared. Thus, the direct analysis of the cross section (measurement part) 3 can be made along a vertical direction B. In this case, the use of the dicing saw for a cutting work ensures highest accuracy. As a result, a characteristic X-ray and Auger electrons emitted from the measurement part 3 enter the detector of a surface analysis device without being interrupted, thereby allowing the surface analysis at high sensitivity.