PROBLEM TO BE SOLVED: To calculate an average value of body temperature in a normal state of a subject in a low temperature period or a high temperature period even when an event that influences a change in body temperature such as medication or drinking occurs during the measurement period of basal body temperature. .. An abnormal data detection unit (32) for detecting abnormal data having a predetermined deviation from the basal body temperature data up to that day out of the acquired basal body temperature data in a plurality of days in the low temperature period or the high temperature period, and the abnormal data. When abnormal data is detected by the detection unit 32, an event inquiry unit 33 that inquires to exclude the abnormal data, and when abnormal data exclusion is specified, the abnormal data is excluded and the basal body temperature in the low temperature period or the high temperature period is excluded. And an average value calculator 34 that calculates the average value of the data. [Selection diagram] Figure 2【課題】基礎体温の測定期間中に服薬や飲酒等といった体温の変化に影響を与えるイベントが発生した場合においても、低温期や高温期における被測定者の通常状態の体温の平均値を算出する。【解決手段】取得した低温期または高温期における複数日の基礎体温データのうちその日前までの基礎体温データに対して所定の偏りを具備する異常データを検出する異常データ検出部３２と、異常データ検出部３２にて異常データが検出された場合に、異常データの除外を問い合わせるイベント問い合わせ部３３と、異常データの除外が指定された場合に異常データを除外して低温期または高温期の基礎体温データの平均値を算出する平均値算出部３４とを有する。【選択図】図２
