A dose delivery device is disclosed where a dose can be set by rotating a dose setting member, whereby a push button is elevated from one end of the device a distance proportional to the set dose from a position fixed relative to the housing, and where the set dose can then be injected by pressing the push button back to its non-elevated position, through which motion a piston rod will move the same or a different distance due to a gearing mechanism being provided between the push button and the piston rod, where the gearing mechanism includes at least a first and a second thread on one or more parts that are rotationally coupled to each other, the first thread engaging a driver, the second thread engaging an element rotationally locked to the driver, one of the threads of the gearing mechanism being left-handed and the other one being right-handed.