In a blood sugar level measuring device, a blood-sugar-level predicting unit predicts a blood sugar level of a user. A light emitting unit irradiates measurement light to the inside of a living organism of the user. A light-emission control unit, a measurement-point-candidate setting unit, a light-amount-control-method determining unit, and a measurement-point selecting unit control a light amount of measurement light per one measurement on the basis of the predicted blood sugar level. A light-reception control unit, a light-absorption-spectrum generating unit, and a blood-sugar-value calculating unit receive reflected light from the user and measure a blood sugar level.