An optical measurement 1 apparatus according to the present invention includes: an irradiation fiber 5 a plurality of light receiving fibers 7 to 9 a light source unit 22 that generates and outputs light to irradiate a biological tissue 6 and supplies the light to the irradiation fiber 5 a measurement unit 23 that has a plurality of measurement units and performs spectrometry on each returned light from the biological tissue, the returned light output by each of the light receiving fibers 7 to 9 and a control unit 26 that causes a predetermined storage unit 27 to store a measurement result by the measurement unit 23, and the measurement unit 23 sequentially performs pre-characteristic-value-obtainment measurement of the returned light under a predetermined condition after power is supplied and, in the pre-characteristic-value-obtainment measurement, starts spectrometry for characteristic value obtainment when an increase in a received light intensity is detected, the increase being an amount set based on an amount of supplied light from the light source unit 22 and a light reflection or scattering state of the biological tissue 6.
