593744 Disclosed is an injection device for administering a fixed dose of a medication. The injection device comprises a housing (2), a dosing element (34) and a piston rod (5). A drive mechanism comprising a drive member (3) is at least partially enclosed within the housing. The housing has an inner thread (4) which engages the drive member. The inner thread has a dose setting section (41) and a dose dispense section (42, see figure 2). The dosing element is permanently fixed relative to the drive member. The piston rod is threadedly engaged with the housing and with the drive member. The dose can be set by rotating the dosing element relative to the housing in a dose setting direction (s) and the dose can be dispensed by pushing the dosing element towards the housing in a longitudinal direction (l). During dose setting the drive member engages the dose setting section of the thread, travelling from position A to position B. During dose cancellation the drive member engages the dose setting section of the thread, but travels in the reverse direction, from position B to position A. During dose dispensing the drive member engages the dose dispense section, travelling from position B to position C.
