A concentration calculation device of the present invention includes an emission unit that emits excitation light to dialysis drainage, a detection unit that detects fluorescence generated from the dialysis drainage, a classification unit that classifies a spectrum of the fluorescence detected by the detection unit into any of a plurality of predetermined groups, and a concentration calculation unit that calculates a concentration of albumin contained in the dialysis drainage on the basis of a calibration model that corresponds to a group of the fluorescence spectrum classified by the classification unit among a plurality of calibration models provided in advance corresponding to each of the plurality of groups, and fluorescence intensities of a plurality of wavelengths in a predetermined wavelength range of a fluorescence spectrum detected by the detection unit.