An injection device for apportioning set doses of a liquid drug from a reservoir comprising: a housing, a rotatable piston rod for driving out the set doses from the reservoir, having an outer thread and a longitudinal non-threaded area, a piston rod guide rotatable during dose expelling only by being provided with a one-way toothing engaging the housing and provided with an inwardly pointing knob engaging the longitudinal non-threaded area of the piston rod to rotate the piston rod during dose expelling, a rotatable drive element for rotating the piston rod guide during dose expelling which drive element is axially movable between a first dose setting position and a second dose expelling position by an axially movable needle shield, wherein the drive element in the first dose setting position is disengaged from the piston rod guide and in the second dose expelling position engages with the piston rod guide, a torsion spring encompassed between the housing and the drive element for rotating the drive element during dose expelling, an End-of-Content tube having an inwardly pointing ridge engaging the non-threaded area of the piston rod, to thereby rotate with the piston rod during dose expelling, and further provided with an outer thread, a rotatable dose setting tube coupled to the drive element and provided with a thread segment threadely engaging the outer thread of the EoC tube, wherein during dose setting rotation of the dose setting tube and the drive element relatively to the piston rod which does not rotate during dose setting causes the EoC tube to move distally an axial distance in relation to the dose setting tube due to the threaded engagement (31, 41) between the rotatable dose setting tube 30 and the EoC tube engaging the piston rod; the axial distance correlating to the size of the set dose and the EoC tube being able to move distally until a proximal stop surface provided on the EoC tube engages the thread segment on the dose setting tube thereby preventing further distal movement of the EoC tube and further rotation of the rotatable dose setting tube, and wherein during dose expelling the dose setting tube, the drive element, the piston rod guide and the EoC tube rotate together maintaining the EoC tube in its relative position in relation to the dose setting tube. a housing, a rotatable piston rod for driving out the set doses from the reservoir, having an outer thread and a longitudinal non-threaded area, a piston rod guide rotatable during dose expelling only by being provided with a one-way toothing engaging the housing and provided with an inwardly pointing knob engaging the longitudinal non-threaded area of the piston rod to rotate the piston rod during dose expelling, a rotatable drive element for rotating the piston rod guide during dose expelling which drive element is axially movable between a first dose setting position and a second dose expelling position by an axially movable needle shield, wherein the drive element in the first dose setting position is disengaged from the piston rod guide and in the second dose expelling position engages with the piston rod guide, a torsion spring encompassed between the housing and the drive element for rotating the drive element during dose expelling, an End-of-Content tube having an inwardly pointing ridge engaging the non-threaded area of the piston rod, to thereby rotate with the piston rod during dose expelling, and further provided with an outer thread, a rotatable dose setting tube coupled to the drive element and provided with a thread segment threadely engaging the outer thread of the EoC tube, wherein during dose setting rotation of the dose setting tube and the drive element relatively to the piston rod which does not rotate during dose setting causes the EoC tube to move distally an axial distance in relation to the dose setting tube due to the threaded engagement (31, 41) between the rotatable dose setting tube 30 and the EoC tube engaging the piston rod; the axial distance correlating to the size of the set dose and the EoC tube being able to move distally until a proximal stop surface provided on the EoC tube engages the thread segment on the dose setting tube thereby preventing further distal movement of the EoC tube and further rotation of the rotatable dose setting tube, and wherein during dose expelling the dose setting tube, the drive element, the piston rod guide and the EoC tube rotate together maintaining the EoC tube in its relative position in relation to the dose setting tube.