The present invention relates to a drive mechanism for use with a medicament delivery device, comprising a plunger rod (68), a drive spring (72) operably arranged to the plunger rod, an actuator (52) comprising a holding member (60) releasably engaged to the plunger rod (68) for holding said plunger rod (68) with said drive spring (72) in a tensioned state, a rotator (38) operably connected and movable relative to said actuator (52) and configured to interact with said holding member for holding said holding member in engagement with the plunger rod, an activator (30) operably connected to said rotator (38). The invention is characterized in that the activator (30) is configured to rotate and subsequently linearly displace the rotator (38) in relation to the actuator (52) such that said holding member (60) is released from the plunger rod (68).
