Abstract: An X-ray fluorescence spectrometer irradiates a measurement sample 1 with primary X rays from an X-ray source, and excites an element in the sample 1 to emit fluorescence X rays and scattered X rays from the sample 1. A spectroscopic system is placed so that a first spectroscopic unit, a second spectroscopic unit, and a single X-ray detector form an optimized optical system. The first spectroscopic unit disperses the fluorescence X rays to collect the resultant X rays onto the X-ray detector. The second spectroscopic unit disperses the scattered X rays to collect the resultant X rays onto the X-ray detector. In this manner, the spectroscopic system disperses the fluorescence X rays and the scattered X rays so that the intensity of the fluorescence X rays and the intensity of the scattered X rays can be detected by the single X-ray detector 24.