The present invention relates to a drug delivery device (100) comprising a housing (101), a threaded piston rod (102), a rotatable drive tube (103), a drive nut (104) in threaded engagement with the piston rod (102) and being rotationally locked but axially moveable relative to the drive tube (103), and a support member (105) arranged rotationally free on the piston rod (102), the support member (105) being axially locked relative to the housing (101) and arranged to allow the drive tube (103) to move axially. The device further comprises a compression drive spring (106) arranged between the piston rod (102) and the drive tube (103), the compression drive spring (106) being arranged axially between the drive nut (104) and the support member (105).
