Abstract: A high pressure metering apparatus for ejecting a fluid such as a polishing aste comprises a housing having a storage chamber, a spring-loaded, stroke-adjustable compressed air piston-cylinder device with a plunger, an injection nozzle, and an adjustable valve device closing the storage chamber off from the injection nozzle. The valve device includes a valve ball and a valve plate. A piston element is fixed to the housing, to which piston element the valve ball is concentrically fixed, and on which a cylinder element is displaceably mounted. The cylinder element is closed by the valve plate of the valve device, which has a valve seat situated opposite the valve ball. The injection nozzle is located downstream of the valve plate and is fixed to the cylinder element. A compression spring bears against the cylinder element and a clamping cap.