The fluid metering device with a modular structure, especially with change gear

The fluid metering device (10), in particular pipetting device, comprising a housing (12) in which a fluid passage for passing a fluid to be metered and, disposed in the liquid line pressure varying mechanism (34) are received, wherein the pressure varying mechanism (34) at least two component arrangements (36, 38) which are movable for producing a pressure gradient in the fluid line relative to each other, wherein in the housing (12) further comprises a dosage is taken, which (by means of a transmission 20) movement and force transmitting manner with the pressure varying mechanism (34) to the at least two component arrangements (36, 38) for relative movement and thus to drive for producing a pressure drop in the liquid line, which is characterized in that the gear (20) in such a manner in two different orientations at respective manufacturing a movement and Kraf t-transmitting connection between dosing and pressure variation means (34) is attachable to the housing (12) that there is any orientation with a different transmission ratio for the motion and power transmission from the dosing to the pressure changing device (34).