The present invention makes it possible to highly accurately estimate an arterial oxygen saturation degree regardless of the environment where a living body is measured and the measurement site. This biological information measuring device is provided with: a first light emission unit that emits light of a first wavelength to a biological tissue in which blood flows； a second light emission unit that is disposed close to the first light emission unit and emits light of a second wavelength that is different from the first wavelength to the biological tissue； a first light receiving unit that receives the light of the first wavelength and the light of the second wavelength having passed through or been reflected by the biological tissue； a second light receiving unit that is disposed close to the first light receiving unit and receives the light of the first and second wavelengths； and a computation processing unit for calculating the change over time in the absorption coefficient of the light of the first wavelength on the basis of the amounts of light of the first wavelength received by the first and second light receiving units, calculating the change over time in the absorption coefficient of the light of the second wavelength on the basis of the amounts of light of the second wavelength received by the first and second light receiving units, and calculating an arterial oxygen saturation degree from the changes over time in the absorption coefficients of the light of the first and second wavelengths.La présente invention concerne un dispositif qui permet d'estimer avec une grande précision un degré de saturation en oxygène artériel, quel que soit l'environnement dans lequel un corps vivant est mesuré et le site de mesure. Ce dispositif de mesure d'informations biologiques comporte : une première unité d'émission de lumière qui émet de la lumière d'une première longueur d'onde vers un tissu biologique dans lequel le sang s'écoule ； une seconde unité d'émission de l
