The method of deciding the central contraction phase blood pressure is disclosed. As for 1st method, the time of the peak in the blood pressure ripple mark of the carotid artery which was measured is decided, next that the blood pressure in the radial blood pressure ripple mark which was measured to the time when it corresponds is decided. 2nd method utilizes only the radial blood pressure ripple mark which was measured. The blood pressure ripple mark is analyzed, the time when the blood pressure ripple mark of the lower half body is shown is decided, the blood pressure of this time is decided. In case of in each case, the blood pressure which is decided substantially is the same as the contraction phase blood pressure of the central aorta.中心収縮期血圧を決定する方法を開示する。第1の方法は、測定された頚動脈の血圧波形におけるピーク時を決定し、次にその対応する時間に測定された橈骨血圧波形における血圧を決定する。第2の方法は、測定された橈骨血圧波形のみを利用する。血圧波形を分析し、下半身の血圧波形を示す時間を決定し、この時の血圧を決定する。いずれの場合も、決定された血圧は、実質的に中心大動脈の収縮期血圧と同じである。
