PURPOSE: To enable quick and highly accurate analysis of a sample without being restricted by the shape and components of the sample, by converting a metal sample containing tin, antimony and copper into a solution to apply a fluorescent X-ray analysis method.

CONSTITUTION: A metal sample containing tin, antimony and copper undergoes a heat decomposition using inorganic acid and oxycarbonic acid. Then, a sample solution obtained is irradiated with X rays to determine a ratio between intensity of reflected X rays from the sample solution and intensity of fluorescent X rays due to a dissolved element. Then, a fluorescent X-ray analysis of a metal element is performed from a relationship between the ratio and the concentration of the element. According to this method, as metal containing tin, antimony and copper is made in the form of a complete solution to stabilize the fluorescent X rays and a fluorescent X ray analysis is applied to enable highly accurate analysis. The fluorescent X rays are characteristic X rays intrinsic to elements to eliminate restraint by quantitative components thereby enabling analysis of multiple components quickly. The intensity of the fluorescent X rays is corrected by the intensity of the reflected X rays thereby achieving a higher accuracy of analysis.