Abstract: To coat a material web of sheet, paper or another carrier material, a flowable coating material is conducted into a distributing chamber consisting of the inner space of a rotatable tube. The coating material is supplied to a wedge-shaped recess whose effective width may be adjusted by turning the tube, via a slot formed through the wall of the tube. The recess is joined in the housing block by a gap ending in an adjustable doctor gap along which the carrier material is moved. The dosing device permits a very accurate determination of the applied thickness of the coating material by fine adjustment.