Abstract: The metering pump comprises a synchronous motor which is stepped down via a mechanical gear and the rotation movement of the motor is converted into a stroke movement which drives the membrane pump. To the motor there is allocated an electronic control which may be activated by external impulses with regard to the delivery quantity. At the same time the control operates such that one always passes through a complete operating cycle of the pump if the nominal delivery quantity resulting on account of the received impulses is as large or larger than the quantity which the pump delivers in an operating cycle.