An optical measurement device includes a light source irradiating a test subject with first light L1 for measuring a degree of oxygen supply to a metabolic system and a photodetector receiving reflected light R1 (or transmitted light) of the first light L1 and second light R2 emitted from the test subject according to a degree of oxygen utilization by the metabolic system. In some cases, the light source irradiates a test subject with excitation light L2 such that the second light R2 is generated. The first light is, for example, light of a wavelength range that is attenuated by being partially absorbed into the test subject by passing through the test subject. Specifically, the first light is light of a wavelength range that is attenuated by being partially absorbed into oxidized hemoglobin or reduced hemoglobin contained in the test subject. The second light is, for example, fluorescence emitted from nicotinamide adenine dinucleotide or flavin adenine dinucleotide.
