PROBLEM TO BE SOLVED: To appropriately determine whether or not blood pressure surge data is affected by a disturbance when analyzing blood pressure time series data to obtain information on blood pressure surge. SOLUTION: For time series data of blood pressure, based on information representing disturbance, one beat reliability representing the reliability of the blood pressure value for each beat is at least a first reliability indicating that it should be used for analysis. And a second reliability indicating that the reliability is lower than the first reliability is determined (S1). From the blood pressure time series data, the blood pressure surge is detected based on a predetermined criterion (S4). For each detected blood pressure surge, the reliability during the surge, which represents the reliability of each blood pressure surge, is obtained based on the one-beat reliability for the plurality of beats forming each blood pressure surge (S5). It is determined whether or not the data of each blood pressure surge is affected by the disturbance based on whether or not the reliability during the surge is equal to or higher than the predetermined surge reliability threshold value (S6). [Selection diagram] Fig. 6【課題】血圧の時系列データを解析して血圧サージに関する情報を得る場合に、血圧サージのデータが外乱の影響を受けているか否かを、血圧サージ毎に適切に判定すること。【解決手段】血圧の時系列データについて、外乱を表す情報に基づいて、一拍毎の血圧値の信頼度を表す一拍信頼度を、少なくとも、解析に用いられるべきことを表す第１信頼度と、この第１信頼度よりも低いことを表す第２信頼度とを含む状態に判定する（Ｓ１）。血圧の時系列データから、予め定められた判定基準に基づいて血圧サージを検出する（Ｓ４）。検出された血圧サージ毎に、各血圧サージをなす複数拍についての一拍信頼度に基づいて、各血圧サージの信頼度を表すサージ中信頼度を求める（Ｓ５）。サージ中信頼度が予め定められたサージ信頼度閾値以上であるか否かに基づいて、各血圧サージのデータが外乱の影響を受けているか否かを判定する（Ｓ６）。【選択図】図６
