A metering device for administering pharmaceutical fluid to the body of a user wherein the pharmaceutical fluid is dispensable in metered manner for the purpose of an infusion or an injection from a reservoir by the advance of a plunger held in the reservoir, the metering device additionally comprising: a) a reusable part comprising a housing, a control unit and a driving device wherein the driving device has a coupling element for transfer of a drive power to a spindle device for advancing the plunger, and the coupling element is fixedly connected to an output wheel of the driving device and has an axial stop for the spindle device; b) at least one disposable part comprising the reservoir and the plunger which is held in the reservoir and can be advanced by the spindle device, wherein the spindle device is disposed on at least one disposable part and has at least one spindle drive with a path of movement per spindle drive wherein the spindle device of the disposable part can be coupled to the reusable part via the coupling element; c) a fluid-carrying connection between the reservoir and the user; and d) a force sensor disposed on the reusable part which measures a reactive force of the spindle device which serves as a measure of the pressure in the reservoir, wherein i) the metering device is designed so that the spindle device of the disposable part is in the retracted state after a partial or complete filling of the reservoir and thus a defined total stroke of the spindle device 2 which is always constant can be travelled, ii) the coupling element is supported axially with a friction bearing and the output wheel is supported on a fixed base via the force sensor wherein because of the fixed connection between the coupling element and the output wheel when the spindle drive comes to rest against the stop the reactive force of the spindle device acting axially on the stop is directed to the force sensor via the output wheel so that there is a direct transfer of force from the stop via the output wheel to the force sensor. a) a reusable part comprising a housing, a control unit and a driving device wherein the driving device has a coupling element for transfer of a drive power to a spindle device for advancing the plunger, and the coupling element is fixedly connected to an output wheel of the driving device and has an axial stop for the spindle device; b) at least one disposable part comprising the reservoir and the plunger which is held in the reservoir and can be advanced by the spindle device, wherein the spindle device is disposed on at least one disposable part and has at least one spindle drive with a path of movement per spindle drive wherein the spindle device of the disposable part can be coupled to the reusable part via the coupling element; c) a fluid-carrying connection between the reservoir and the user; and d) a force sensor disposed on the reusable part which measures a reactive force of the spindle device which serves as a measure of the pressure in the reservoir, i) the metering device is designed so that the spindle device of the disposable part is in the retracted state after a partial or complete filling of the reservoir and thus a defined total stroke of the spindle device 2 which is always constant can be travelled, ii) the coupling element is supported axially with a friction bearing and the output wheel is supported on a fixed base via the force sensor wherein because of the fixed connection between the coupling element and the output wheel when the spindle drive comes to rest against the stop the reactive force of the spindle device acting axially on the stop is directed to the force sensor via the output wheel so that there is a direct transfer of force from the stop via the output wheel to the force sensor.