Deterioration measurement device, system, method, and lubricant oil composition

A deterioration measurement device comprising:

• a light emitter that emits an irradiation light toward a measurement target object, wherein the measurement target object comprises a fluorescent compound that emits a fluorescent light upon reception of the irradiation light;
• a light receiver that receives the fluorescent light emitted by the fluorescent compound and transmits a signal in accordance with the received fluorescent light;
• and
• a sensor that senses a deterioration of the measurement target object on a basis of the signal transmitted by the light receiver.

A deterioration measurement method comprising:

• emitting an irradiation light toward a measurement target object comprising a fluorescent compound that emits a fluorescent light in response to the irradiation light;
• receiving the fluorescent light emitted by the fluorescent compound;
• transmitting a signal in accordance with the received fluorescent light;
• and
• sensing a deterioration of the measurement target object on a basis of the transmitted signal.