A metering pump unit with a metering chamber (6), a positive-displacement body that adjoins the latter and can be moved by a positive-displacement drive (22), as well as a controller (30) for actuating the positive-displacement drive (22). The controller (30) is designed to actuate the positive-displacement drive (22) at least in a specific operating state in such a way that a stroke, in particular a pressure stroke, of the positive-displacement body is started at a first, lower stroke rate, and the stroke rate is increased to a second, elevated stroke rate as the pressure stroke (36) continues. A method is provided for controlling the positive-displacement drive (22) of such a metering pump unit.