An object of the present invention is to provide an optical measurement device that can measure a living tissue at an S/N ratio maintained without increasing the length of the measurement time. An optical measurement device 3 includes: an illumination control unit 332a that causes a measurement light source unit 321 to execute alternately emission and stoppage of measurement light within the time from the start to end of the measurement by the optical measurement device 3, and causes the measurement light source unit 321 to emit the measurement light such that the emission time during which the measurement light source unit 321 emits the measurement light is longer than the stoppage time during which the measurement light source unit 321 stops the measurement light and a computation unit 332b that removes, from an intensity of return light of the measurement light detected by a first detection unit 325, a detected intensity of return light of observation light from the endoscope device and reflected from a living tissue S1.
