The invention relates to a pneumatic ventricular assist device. The inventive device is designed such that it can be used in any short- or long-term transoperative circulatory support systems including right ventricular assist devices (RVAD), left ventricular assist devices (LVAD) and biventricular assist devices (BIVAD) which can be implanted using a catheter or which take the form of extracorporeal devices. The device consists of a smooth pumping casing and a disposable pumping unit comprising a pumping bag, two one-way valves and tube connectors. The aforementioned pumping unit has been specially designed in order to enable the continuous, fluid movement of the blood and to limit the surfaces with which the blood comes into contact. Said pumping unit is made from a flexible, elastic material such as silicon. The components can be made economically and reliably by means of injection moulding. Furthermore, the pumping casing and the pumping unit comprise complementary characteristics which enable the pumping unit and any associated cannula to be positioned quickly and safely.