PURPOSE: To enable depth from the sample surface to be selected, and provide a correct analysis result by changing the irradiation angle of a primary X-ray relative to the sample surface and the takeout angle of a fluorescent X-ray.

CONSTITUTION: Regarding the analysis of silicon in an aluminum alloy, critical depth becomes 0.21μm and 0.30μm respectively for the irradiation angle θ of 90 degrees and takeout angle ψ of 30 degrees, and irradiation angle θ of 30 degrees and takeout angle ψ of 90 degrees. When an ordinary type cover 2 with a mask 3 kept in parallel to the bottom of a sample holder body 1 is used, the critical depth is 0.21μm, while the critical depth is 0.30μm when a cover 2 with the mask 3 inclined relative to the bottom of the holder body 1 is used. As a result, analysis information on a deeper position can be obtained by keeping a sample inclined by 60 degrees. The content of silicon is an average at depth within the range of 0.21μm to 0.30μm from the sample surface. When the silicon is particularly dense at the extreme surface of the sample, analysis data available from the latter system having the inclined cover 2 shows average silicon concentration more accurately. Also, information on the degree of silicon segregation can be obtained from data of both systems.