PURPOSE: To reduce the influence of ruggedness on the sample surface to perform accurate measurement, by detecting the height of the sample on a basis of the emission stereoscopic angle of fluorescent X-rays or continuous X-rays from the sample and by changing the position of the sample stand on a basis of this detection.

CONSTITUTION: When slab sample 2 is carried in the direction of arrow 21, the height of the sample surface just under electron gun 4 is fluctuated as shown by virtual line 22 according to the flat degree of the upper face of sample 2. When irradiation point P of electron beam 5 will come off from optical axis 13 of spectroscope 12, shadow is generated by upper and lower edges of the lower end part of the first collimator 7, and therefore, the X-ray incident quantity becomes different between ionization chambers 14 and 15, and a current is supplied to servo motor 20 for the purpose of correcting this difference, and sample stand 3 is driven vertically in the direction of arrow 23, so that the element content of each part can be analyzed accurately independently of the flat degree of the sample surface.