The biological signal processing apparatus includes a biological signal extraction unit (2) that extracts a biological signal from an electrocardiogram waveform measured by the electrocardiograph (1), and time-series data of the biological signal extracted by the biological signal extraction unit (2). Whether the data of the biological signal extracted by the averaging processing unit (3) and the biological signal extraction unit (2) used to calculate the averaged data is appropriate is the data of the biological signal at a past time than this data An abnormal value determination unit (4) that determines for each data based on the averaged data calculated using, and deletion or interpolation of the data of the biological signal determined to be inappropriate by the abnormal value determination unit (4) And an abnormal value processing unit (5) for performing the above.生体信号処理装置は、心電計（１）が測定した心電図波形から生体信号を抽出する生体信号抽出部（２）と、生体信号抽出部（２）で抽出された生体信号の時系列データを用いて平均化データを算出する平均化処理部（３）と、生体信号抽出部（２）で抽出された生体信号のデータが適切かどうかを、このデータよりも過去の時刻の生体信号のデータを用いて算出された平均化データに基づいてデータ毎に判定する異常値判定部（４）と、異常値判定部（４）で不適切と判定された生体信号のデータの削除および補間のいずれかを行う異常値処理部（５）とを備えている。
