There is provided a living body light measuring device capable of
monitoring a time curve of a blood substance concentration as time curves
of parameters of a signal waveform and judging or analyzing
characteristic traits of a subject relevant to the parameters of the
signal waveform, wherein a signal processor extracts parameters such as a
peak value and latency from a hemoglobin signal waveform measured before
and after substance intake of a testee, and generates and displays a time
curve graph having a parameter and time respectively as its ordinate and
abscissa. Influence of an intake substance upon blood component
concentrations and blood flow can be monitored by monitoring the time
curves of parameters of the signal waveform. A category processor
classifies measurement data into categories, analyzes time curves of a
plurality of parameters every category, and displays a result on a result
viewer.