The invention relates to a milk collecting device and a method for operating a milk collecting device, comprising a milk collecting vessel with an inlet and a controllable outlet and a measuring device, said measuring device comprising a first electrode and a second electrode at a separation from the first electrode, a power supply electrically connected to both electrodes and a measuring device for recording an electrical parameter. The power supply is connected to two connection points on the first electrode at a separation from each other such as to be in parallel with relation to the first electrode and connected to the second electrode by the measuring device in order to determine a characteristic measure for the filling level of a liquid in the milk collecting vessel.