The present disclosure provides a measuring device for biological tissue by using an optical sensor, the device being compact enough to fit in a user's hand and casually usable by the user. The measuring device is provided with: an optical sensor that measures optical data about an object of measurement through a measurement surface in contact with the object of measurement by irradiating the object of measurement with light from a light emitter and causing a light receiver to receive reflected light that is reflected from the object of measurement, the object of measurement being a portion of biological tissue; a temperature sensor that measures the temperature of the optical sensor; and a data processor that processes the optical data on the basis of the temperature of the optical sensor and derives a measurement result pertaining to the object of measurement on the basis of the processed optical data.