It is intended to provide a method of using the optical measurement technology non-invasive, to understand the mental state of the individual mood and emotion. In the optical measurement apparatus having an optical detecting means and the light irradiating means, the intensity of the light is presented (the first problem, the second problem at least) the problems with different to the subject, detected by said light detecting means calculating a hemoglobin signal based on the deoxygenated hemoglobin concentration change and oxygenated hemoglobin in the interior of the subject, the hemoglobin signal of the measurement point for a given first problem, the measurement points given in the alternative to the second problem I want to calculate the relative value using the hemoglobin signal.非侵襲な生体光計測技術を用い、気分、感情など個人の精神状態を把握する方法を提供する。光照射手段と光検出手段を有する生体光計測装置において、被検体へ異なる複数の課題(少なくとも第一の課題、第二の課題)を呈示し、前記光検出手段で検出された光の強度から前記被検体の内部における酸素化ヘモグロビンおよび脱酸素化ヘモグロビン濃度変化に基づくヘモグロビン信号を算出し、第1の課題に対する所定の計測点のヘモグロビン信号と、第2の課題に対する別の所定の計測点のヘモグロビン信号とを用いた相対値を算出する。
