The present invention relates to optical fiber photometry. An optical brain signal measurement device (100) according to one embodiment may comprise: a light source unit (110); an excitation filter unit (120); a first segmentation/concatenation unit (130); a second segmentation/concatenation unit (140); an emission filter unit (150); and a measurement unit (160). The optical brain signal measurement device (100) can segment or concatenate optical signals through a segmentation/concatenation unit while transmitting the signals to a brain signal measurement target through an optical fiber having directivity, and identify the wavelength range to which each of multiple signals correspond through a spectrometer to obtain multiple brain signals (multiple light sources) by using the light source directivity of the optical fiber and the spectrometer without a dichroic filter.
