Patent ID: 8309920

Claim:
A sample milling/observing apparatus comprising: an ion gun which irradiates an ion beam onto a sample to form an observed section; a tiltable stage that tilts the sample within a predetermined range greater than zero; an electron gun which irradiates an electron beam onto said observed section formed by said ion gun; a focal point adjusting unit which can adjust a relationship between said observed section and a focal point of said electron beam; and a focal point control unit which controls said focal point adjusting unit on the basis of an amount of cut of said sample obtained by irradiation of said ion beam obtained by said ion gun; wherein said focal point adjusting unit and said focal point control unit are configured to automatically adjust said focal point of said electron beam to said observed section in accordance with said amount of cut of said sample such that a thickness of the cut d and a tilt angle formed between the stage and a horizontal direction θy determine a moving distance δ of a set reference point according to: δ= d /cos θ y.