A blood glucose measurement device, a blood glucose calculation method, and a blood glucose calculation program capable of accurately measuring a blood glucose level by using light are provided. The blood glucose measurement device includes a light source 11 that outputs measurement light L1 to be input to a living body 50； a light detector 12 that detects the measurement light L1 propagated inside the living body 50 and generates a detection signal in accordance with an intensity of the measurement light LI； and a computation unit that obtains a time lag between a temporal change in a first parameter related to an oxygenated hemoglobin concentration and a temporal change in a second parameter related to a deoxygenated hemoglobin concentration based on the detection signal, and obtains the data related to the blood glucose level based on the time lag.
