A medicament delivery device comprising: - a housing (10, 12); - a penetration and withdrawal mechanism, for actuating a penetration and a withdrawal sequence, the penetration and withdrawal mechanism comprising a medicament delivery member and a rotator sleeve having a pinion; - a medicament container connection mechanism, for connecting a medicament container with the medicament delivery member, the medicament container connection mechanism comprising a piercer slidably arranged in the housing (10, 12), the piercer comprising a piercing needle; - a medicament delivery drive unit, for expelling a medicament, the medicament delivery drive unit comprising an electric motor, a plunger rod element and an electrical circuit having a second lead and a third lead; - an activation mechanism, for initiating a penetration and medicament delivery sequence; and - a stop mechanism (15, 121), for initiating a withdrawal sequence; characterized in that the medicament delivery device further comprises: - a control mechanism comprising a plate-shaped control member, linearly movable between a first position and a second position inside a compartment of the housing (10, 12), the control member comprising a toothed rack; wherein linear movement of the control member between the first position and the second position causes rotation of the rotator sleeve via interaction between the pinion and the toothed rack; wherein linear movement of the control member between the first position and the second position causes the piercing needle to penetrate a septum of the medicament container to thereby establish a fluid connection between the medicament container and the medicament delivery member; wherein the control member comprises a conductive surface to which the second lead and the third lead are connected when the control member is in the second position such that the electrical circuit is closed, allowing a current to flow through the electrical circuit to drive the electric motor to thereby move the plunger rod element into the medicament container for expelling a dose of medicament; wherein the activation mechanism comprises a manually actuated first locking element and wherein the control member comprises a first seat in which the first locking element is accommodated, such that the control member is connected to the activation mechanism when the control member is in the first position; wherein the control member is further releasably held in the first position by the first locking element against a bias of a pre-tensioned first force element, and wherein manual actuation of the first locking element releases the control member to move linearly from the first position towards the second position under the bias of the first force element; wherein the stop mechanism comprises a manually actuated second locking element and wherein the control member comprises a second seat in which the second locking element may be accommodated, and configured such that the control member is connected to the stop mechanism when the control member arrives at the second position; and wherein the control member is arranged to be releasably held in the second position by the second locking element against a bias of a pre-tensioned second force element, and wherein manual actuation of the second locking element releases the control member to move linearly from the second position towards the first position under the bias of the second force element. - a housing (10, 12); - a penetration and withdrawal mechanism, for actuating a penetration and a withdrawal sequence, the penetration and withdrawal mechanism comprising a medicament delivery member and a rotator sleeve having a pinion; - a medicament container connection mechanism, for connecting a medicament container with the medicament delivery member, the medicament container connection mechanism comprising a piercer slidably arranged in the housing (10, 12), the piercer comprising a piercing needle; - a medicament delivery drive unit, for expelling a medicament, the medicament delivery drive unit comprising an electric motor, a plunger rod element and an electrical circuit having a second lead and a third lead; - an activation mechanism, for initiating a penetration and medicament delivery sequence; and - a stop mechanism (15, 121), for initiating a withdrawal sequence; - a control mechanism comprising a plate-shaped control member, linearly movable between a first position and a second position inside a compartment of the housing (10, 12), the control member comprising a toothed rack;