To provide a method for analyzing a chamfered part in which an impurity particle existing in a thin film-like state, a metal or an organic impurity adhered to the chamfered part of a substrate such as a semiconductor wafer or the like can be identified by a point analysis.

In the method for analyzing the impurity adhering to the chamfered part of the substrate, as analyzing means, an extraction electrode plate 14 and a sample electrode plate 13 are provided. A secondary ion analyzer for detecting a secondary ion generated by irradiating the surface of a sample placed at a predetermined position between the electrode plates with an ion beam is used, the method comprises the steps of inclining the sample 10 of the substrate including the chamfered part 11, holding the surface 12 to be analyzed of the chamfered part in parallel with the electrode plates at the predetermined position, and analyzing the chamfered part. The holding jig for the chamfered part comprises two inclined surfaces in parallel and opposite to each other, and the sample held between the inclined surfaces.