The present invention relates to a medicament delivery device comprising a generally tubular distal housing part (18); a generally tubular proximal housing part (12) releasibly connected to said distal housing part; a medicament container (70) having opposite proximal and distal ends and a slidable stopper, wherein the container is partially and slidably arranged within the proximal housing part; a plunger rod (72) having opposite proximal and distal ends and being arranged within said distal housing, wherein the proximal end of the plunger rod is abutting the stopper of the container; drive means arranged within said distal housing and being operably connected to said plunger rod for driving said plunger rod and thereby said stopper towards the proximal end of the device; characterised in that the device further comprises a priming device (34) having a distal end comprising tune engagement means (38) arranged to cooperate with corresponding tune engagement means (24) arranged at the proximal housing, an end wall (46) abutting the proximal end of the container, a passage (48) arranged on said end wall, and a proximal end comprising delivery member engagement means (42) arranged to cooperate with corresponding delivery member engagement means arranged on a delivery member; wherein the priming device (34) is arranged and designed such that a tune distal displacement of the priming device in relation to the proximal housing part causes a distal displacement of the container (70) in relation to the plunger rod (72), whereby the plunger rod force the stopper to be proximally displaced and thereby a priming of the container is performed.