However, there is the inconvenience of using the cuff attached to the patient's arm for non-invasive BP measurement and also the limitation in measuring the blood pressure continuously.Recently, the continuous and non-invasive the BP measurements using PTT, in inversely linear relationship with blood pressure, have been extensively accomplished in the past few decades. Park [3], and Lass [4] estimated the blood pressure using time interval between the R-peak ofelectrocardiogrm (ECG) and the characteristic points of the pulse wave signal, such as the base line point of pulse wave, maximum point, and point indicating 50% of the pulse wave amplitude. Also Teng [5] estimated the blood pressure using the systolic and the diastolic peak of PPG signal, and the pulse width of the pulse wave. The blood pressure measuring method using these pulse waves induces the inconvenience of needing additional information, such as body parameter to improve the accuracy despite simplicity of measurement. In this study, the estimating algorithm of the BP was proposed using the PTT calculated from the time difference between peculiar points of pressure pulse and photoplethysmography measured at identical region with QRS peak of ECG.