Abstract: The present invention concerns a displacement pump comprising a delivery chamber connected to a pressure and a suction connection, a displacer element which determines the volume of the delivery chamber and which can be reciprocated between a first position in which the delivery chamber is of a smaller volume and a second position in which the delivery chamber is of a larger volume, wherein the pressure connection is connected to the delivery chamber by way of a pressure valve and the suction connection is connected to the delivery chamber by way of a suction valve. To provide a corresponding displacement pump which is self-venting, of a simple construction and also has a pressure-stable metering capacity even at high counteracting pressures in the pressure line, it is proposed according to the invention that a reservoir which can be filled with delivery fluid is connected to the delivery chamber by way of a gas venting valve.