An apparatus for stuffing a shirred tubular casing with a fluid material such as a sausage composition or pieces of ham comprising a stuffing horn having an aperture through which the fluid material is forced under pressure into the casing, a device located on the periphery of the stuffing horn and within the interior of the casing for smoothing and expanding the casing, the device comprising at least two disk-shaped planar bodies, at least one of which is rotatable in a plane parallel to and/or shiftable perpendicular to the longitudinal axis of the stuffing horn, the outer circumference of each planar body being smaller than the inner circumference of the tubular casing, whereby the projection of the cross-sectional surfaces of the planar bodies in the direction of the longitudinal axis upon rotating or shifting of the bodies results in a total surface having a greater circumference than the inner circumference of the tubular casing.