A medicament delivery device comprising: - a tubular housing, having opposite proximal and distal ends, - a tubular activation member, slidably and coaxially arranged inside the tubular housing and comprising a proximal annular contact member; - a first resilient member arranged at the distal end of the tubular activation member for moving it in a proximal direction from a non-activated position, wherein the annular contact member is in contact with the proximal end of the housing, to an activated position, wherein the annular contact member is at a predetermined distance from the proximal end of the housing; - a container holder coaxially arranged within the tubular activation member and fixedly attached to the tubular housing; - a medicament container arranged within said container holder housing a slidable stopper; - a tubular operation member rotatably arranged between the container holder and a tubular extension part at the distal end of the housing and comprising first co-acting means interactively connected to corresponding first co-acting means of the tubular activation member; - a plunger rod and a second resilient member, wherein the proximal end of said plunger rod is in contact with the stopper, the plunger rod comprising second co-acting means interactively connected to corresponding second co-acting means of the tubular operation member; and - a delivery member; characterized in that the container is a cartridge, having a membrane and in that the delivery member comprises a retainer member fixedly connected to the container holder, a hub coaxially movable within the retainer member, a needle having opposite proximal and distal ends and being fixedly attached to the hub, and a cap interactively connected to the hub and to the retainer member, wherein the cap comprises a distal end surface abutting with the proximal end surface of the annular contact member such that when said cap is manually operated, the hub is distally moved whereby the distal end of the needle penetrates the membrane and the cap is detached from the retainer member, allowing the tubular activation member to be moved by the force from the first resilient member from its non-activated position to its activated position. - a tubular housing, having opposite proximal and distal ends, - a tubular activation member, slidably and coaxially arranged inside the tubular housing and comprising a proximal annular contact member; - a first resilient member arranged at the distal end of the tubular activation member for moving it in a proximal direction from a non-activated position, wherein the annular contact member is in contact with the proximal end of the housing, to an activated position, wherein the annular contact member is at a predetermined distance from the proximal end of the housing; - a container holder coaxially arranged within the tubular activation member and fixedly attached to the tubular housing; - a medicament container arranged within said container holder housing a slidable stopper; - a tubular operation member rotatably arranged between the container holder and a tubular extension part at the distal end of the housing and comprising first co-acting means interactively connected to corresponding first co-acting means of the tubular activation member; - a plunger rod and a second resilient member, wherein the proximal end of said plunger rod is in contact with the stopper, the plunger rod comprising second co-acting means interactively connected to corresponding second co-acting means of the tubular operation member; and - a delivery member; characterized in that