A blood purification device allows controlling a false alarm and allows detecting accurately an abnormality in a patient who is undergoing a blood purification treatment or in the device which is running. The hemodialysis equipment includes blood circuit made of an arterial blood circuit having an arterial needle at its end and a venous blood circuit having a venous needle at its end； a blood pump； a dialyzer purifying the blood flowing in blood circuit ； a venous blood pressure sensor which can detect pressure of a patient's blood flowing in the venous blood circuit； a venous blood pressure monitoring means for comparing a base value of the pressure measured by the venous blood pressure sensor or pressure predicted to be measured with a predetermined alarm-threshold. The device also has a venous blood pressure monitoring means allows updating the predetermined alarm threshold at a predetermined period of time.
