A drug delivery device adapted to receive a cartridge and comprising a housing, an expelling assembly with a threaded piston rod, a threaded nut and a drive element arranged in non-rotational engagement with the piston rod, a drive coupling actuatable between a resetting state in which the piston rod can be moved proximally, and an operational state in which the drive element can drive the piston rod distally, wherein the drive element and the threaded nut are not moved axially relative to the housing when the drive coupling is actuated.
