Abstract: An intensity distribution acquirer acquires a first detected intensity distribution detected by a detector with a sample position at which a sample is not present irradiated with light by a standard light source, and acquires a second detected intensity distribution detected by the detector with the sample position at which a sample is not present irradiated with light by an irradiation light source during a first measuring work. An irradiation intensity calculator calculates a radiation intensity at each wavelength of irradiation light of the irradiation light source based on the first detected intensity distribution, the second detected intensity distribution and radiation characteristics of the standard light source. An irradiation photon count calculator calculates an irradiation photon count at each wavelength of irradiation light of the irradiation light source based on an irradiation intensity at each wavelength.