Provided are a quantitative analysis method, a quantitative analysis program, and an X-ray fluorescence. The quantitative analysis method includes: a step of acquiring a representative composition set to represent contents of analysis components; a step of acquiring a plurality of comparative compositions, in each of which the content of one of the analysis components of the representative composition is changed by a predetermined content; a detection intensity calculation step of calculating a detection intensity indicating an intensity of fluorescent X-rays detected under the influence of the geometry effect through use of an FP method with respect to a virtual sample having a thickness set in advance and being indicated by each of the representative composition and the comparative compositions; and a step of calculating a matrix correction coefficient for each of the analysis components based on the detection intensity.