A blood-vessel recognition blood-flow measurement method including: obtaining a real-time Doppler spectrum by performing a Fourier transform on a temporal waveform of the intensity of scattered light of laser light in a living body； calculating a normalized real-time Doppler spectrum and a normalized zero spectrum； calculating a region spectrum from a subtracted spectrum that is calculated through subtraction of these calculated spectra； calculating a PS reference spectrum by subtracting, from the region spectrum, the maximum value of the region spectrum in a predetermined PS reference region； calculating an average frequency on the basis of a computational spectrum that is obtained by replacing an element of which the PS reference spectrum is negative with zero； and determining a blood flow velocity by comparing the calculated average frequency with a predetermined threshold.
