The invention relates to a driver for a pneumatic ventricular assistance device (VAD) which is actuated by pressurised air, oxygen or any other gas that is commonly available in hospital rooms, intensive care units and operating theatres. The inventive driver can supply both blood ejection pressure (systole) and blood filling vacuum pressure (diastole) to the VAD. According to the invention, the driver is controlled by a digital/computer controller by means of pressure and volume sensors and electromechanical valves. The ventricular pumping is performed by a single spring-driven bellows or piston. Moreover, the computer can actively regulate the maximum systolic ventricular pressure, the maximum diastolic pressure drop, the rhythm of the cycles and/or the ej ection volume (depending on the operating mode). The driver can also ventilate the drive conduit automatically and periodically in order to remove condensation and vitiated air therefrom. The device comprises no motor nor electrical pump and, as a result, is small, reliable, easy to manage and less expensive.