The invention refers to a handheld injection device comprising a housing (10, 20, 30), a piston rod (60), defining a first longitudinal axis (I) and located within the housing (10), a driver (70, 80, 90) coupled to the piston rod (60), a dose setting means (40), which is rotatable during dose setting, a power reservoir (100) for driving the driver (70, 80, 90), and a number wheel (130) for displaying a dose set by the dose setting means (40).