Abstract: There is disclosed a cell culture apparatus particularly suitable for the culture of viable, shear sensitive cells, either grown in suspension or attached to a substrate such as microcarrier beads. The apparatus comprises a cell culture compartment and a compensation chamber disposed thereabove and serving to maintain sterile conditions for the cell culture compartment operating in a zero-headspace mode. The cell culture compartment comprises a gas exchange tube connected to an outside source of gas and defining a downflow zone and a central upflow zone in the cell culture compartment. An Archimedean screw-type auger is installed coaxially in the cell culture compartment to provide a circulating flow of liquid therein. The turbulence of the flow is reduced by the provision of an upper and lower flow guide surface.