Provided is an optical measurement device that can measure the balance between the supply and utilization of oxygen in the metabolism of a subject. An optical measurement device (20) is provided with: a light source (21) that radiates toward a subject (24) a first light (L1) that is for measuring the degree of oxygen supply to a metabolic system; a photodetector (22) that receives reflected light (R1) (or transmitted light) of the first light (L1) and receives second light (R2) that is emitted from the subject in accordance with the degree of oxygen utilization by the metabolic system. In some cases, the light source (21) radiates excitation light (L2) toward the subject (24) in order to generate the second light (R2). The first light is light that, for example, as a result of passing through the subject, is partially absorbed by the subject and is in an attenuated wavelength band. Specifically, the first light is light that is partially absorbed by oxidized hemoglobin or reduced hemoglobin contained in the subject and is in an attenuated wavelength band. The second light is, for example, fluorescence emitted by nicotinamide adenine dinucleotide or flavin adenine dinucleotide.