Abstract: In an apparatus irradiating a specimen with a scanning charged-particle beam to detect x-rays or backscattered electrons emanating from the specimen to display an image thereof on a viewing screen, the beam is fixed on a certain point on the specimen to analyze only that region. The size of the analyzed region is indicated on the viewing screen by a circle, for example, and this circle is superimposed on the image of the specimen. The size of the circle is determined from the accelerating voltage at which the beam is accelerated, the magnification of the image of the specimen, and the mean atomic number of the specimen.