The present invention relates to a device for the continuous monitoring of characteristic blood quantities in extracorporeal circulation circuit, comprising a venous line which conveys the blood from the patient to an oxygenator device and an arterial line which conveys the blood from the oxygenator back to the patient.The peculiar feature of the invention resides in the fact of comprising:- a sensor connected to the venous line and a sensor connected to the arterial line suitable for continuous measuring the quantities represented by venous saturation of the oxygen and by arterial saturation of the oxygen, respectively；- two sensors fitted in some points of the extracorporeal circuit, suitable for continuous measuring the quantities represented by blood flow and haemoglobin；- means suitable for data entering by the operator；- a monitor having a micro processor and a display screen.
