PROBLEM TO BE SOLVED: To provide a biological information processor capable of acquiring cycle fluctuation components relevant to day cycle of the temperature from the temperature of an organism measured in a predetermined time zone.SOLUTION: The biological information processor, includes: a temperature measuring unit that measures the temperature in a predetermined part; and a calculation processing unit that calculates a day cycle part curved line of the temperature formed in a smooth curved line based on the time change of the temperature in a predetermined time zone. The biological information processing method may include the steps of: measuring temperature on a predetermined part; and calculating a day cycle part curved line of the temperature formed in a smooth curved line based on the time change of the temperature in a predetermined time zone.SELECTED DRAWING: Figure 7【課題】所与の時間帯で測定した生体の温度から、当該温度の日周期に係る周期変動成分を取得すること。【解決手段】所定部位の温度を測定する測温部と、所与の時間帯の前記温度の時間変化に基づいて、滑らかな曲線でなる前記温度の日周期部分曲線を算出する演算処理部と、を備えた生体情報処理装置である。所定部位の温度を測定することと、所与の時間帯の前記温度の時間変化に基づいて、滑らかな曲線でなる前記温度の日周期部分曲線を算出することと、を含む生体情報処理方法を構成してもよい。【選択図】図7