This biological information processing device is provided with: a peak detection unit for detecting the peaks of a biological signal generated in a cardiac cycle; a waveform clipping unit for clipping out a first peak-to-peak biological signal between two peaks, which are adjacent on the time axis of the biological signal, on the basis of detection results of the peak detection unit; and a resampling unit for transforming the first peak-to-peak biological signal to a second peak-to-peak biological signal for a prescribed number of samples. The biological information processing device is further provided with: an orthogonal transformation unit for generating orthogonal transformation coefficients by performing an orthogonal transformation on the second peak-to-peak biological signal; a differential processing unit for generating a differential signal for the orthogonal transformation coefficients on the time axis; and an encoding unit for encoding the differential signal.