An injection device for injection of set does of medicine from a cartridge has a nut that is screwed up along a threaded piston rod during a dose setting operation. The nut is screwed along the piston rod by rotating a dose setting drum. An injection button is coupled to the piston rod with a gear wheel transmission. Axial movement of the injection button causes a corresponding axial movement of the piston rod until the nut engages an abutment in the housing.