The present invention detects a fluorescent signal from AGEs at a blood vessel tissue of an individual to determine the condition of the tissue of the individual. This solves a problem that in measurement of AGEs used in diagnosis of diabetes, data indicative of fluorescent spectrum from AGEs at the skin of a forearm varies depending on where to measure on skin of even the same forearm, which results in variations in measurement values, leading to unreliable data and incorrect measurement result.
