The present disclosure discloses a frequency domain (FD)-based multi-wavelength bio-signal analyzing apparatus including: four or more light sources configured to irradiate frequency-modulated light at four or more different discrete wavelengths； at least one light detector configured to detect an output light reflected and introduced from a subject； and a processing circuit connected to the four or more light sources and the at least one light detector and configured to calculate a scattering coefficient and an absorption coefficient at each discrete wavelength based on an output light detected by the at least one light detector and calculate a concentration of a chromophore present in the subject based on the scattering coefficient and the absorption coefficient at each discrete wavelength. Herein, the processing circuit drives at least two of the four or more light sources based on the chromophore present in the subject.
