An optical measurement device includes: a measurement light source unit that emits measurement light; measurement probe including an illumination fiber configured to radiate the measurement light to a living tissue, and a light-receiving fiber configured to receive return light of the measurement light reflected and/or scattered from the living tissue; a detection unit that detects the return light; an illumination control unit that causes the measurement light source unit to execute alternately emission and stoppage of the measurement light during the measurement and to emit the measurement light such that the emission time is longer than the stoppage time; and a computation unit that removes, from an intensity of return light of the measurement light detected by the detection unit, a detected intensity of return light of the observation light radiated by an endoscope and reflected from the living tissue.