A dosing device with a dosing chamber unit receiving dosing fluid and actively ejecting dosing fluid, which includes at least one dosing chamber, an inflow channel which fluidically connects a dosing chamber with an inlet and in an inflow orifice opens into the dosing chamber, and a backflow channel which fluidically connects the or a dosing chamber with a backflow and which in a backflow orifice proceeds from the associated dosing chamber, is able to exactly eject minimum amounts of fluid. Inflow and backflow orifice are spaced from each other. A 3-way valve is provided with a common port for the inflow and the backflow channel.