An electronic blood pressure monitor retrieves a pulsewave signal that is superimposed on a cuff pressure signal and indicates a pulsewave at a measurement site, and acquires a string of pulsewave amplitudes indicated by the pulsewave signal. A first envelope connects the amplitudes created for the acquired string of pulsewave amplitudes. Local maxima and minima in the first envelope are detected. With respect to the strings of amplitudes corresponding respectively to the local maxima and minima, a local-maximum envelope and a local-minimum envelope connecting the amplitudes are created. Two pressure values at points at which portions on the high-pressure-side and low-pressure-side with respect to the maximum peaks of the local-maximum envelope and the local-minimum envelope respectively cross first and second threshold levels are obtained, and the average values of each pair of pressure values are calculated as the systolic blood pressure and the diastolic blood pressure respectively.
