It is desirable to minimize discomfort of a living body due to pressing by a blood pressure monitoring system of a type which monitors the blood pressure of the living body for a long period of time. The present invention is constituted by including pulse wave detecting device for detecting pulse waves of an arterial vessel of a living body, blood pressure measuring device for measuring an actual blood pressure of the living body, and control device for determining a relationship between the pulse waves detected by the pulse wave detecting device and the actual blood pressure measured by the blood pressure measuring device, determining blood pressures according to the thus-determined relationship and based on the pulse waves, and commanding a display to continuously display the thus-determined blood pressures thereon. In accordance with the present invention, blood pressures are determined according to the relationship between the actual blood pressure and the pulse waves, which is determined by the control device, and based on the pulse waves, and the thus determined blood pressures are continuously displayed, thereby eliminating the operation of successively obtaining measurements of the actual blood pressure by using a cuff, for example, and minimizing discomfort felt by the living body.