Disclosed is a biological optical measurement instrument provided with: a light source unit which has a light-emitting unit that emits light and irradiates the light to an object a light measurement unit configured to measure passing light at a measurement point of the object: a signal processing unit configured to process hemoglobin information outputted from the light measurement unit and create a light measurement image and a display unit configured to display the light measurement image, further provided with a measurement/determination unit configured to measure the deterioration state of the light-emitting unit from the light output of the light-emitting unit and an electric current injected into the light-emitting unit and determine the necessity/unnecessity of replacement of the light-emitting unit, wherein the display unit displays information relating to the necessity/unnecessity of replacing the light-emitting unit determined by the measurement/determination unit.
