Injection device comprising - a housing (2, 3, 4, 5), - a container holder arranged movable in a longitudinal direction within said housing, said container holder being configured for accommodating a medicament container having a needle attached to one end thereof and a stopper sealingly and slidable arranged inside said medicament container at the other end thereof, - a plunger rod being arranged with a proximal end thereof contactable with said stopper, - a first and a second energy accumulating member arranged in the interior of the housing of the injection device (1, 100, 200) and adapted to accumulate and store energy, - plunger drive means (50, 70) being slidable arranged in relation to the plunger rod, being rotationally locked to the plunger rod and being rotatable in relation to the housing (2, 3, 4, 5), said plunger drive means (50, 70) being operationally associated with said first energy accumulating member, - a container driver attached to the container holder and threadedly connected to the plunger rod, said container driver being connected to said second energy accumulating member such that due to an output axial force from said second energy accumulating member, the container driver, the container holder and the plunger rod are axially moveable in relation to the housing (2, 3, 4, 5) a predetermined distance towards the proximal end of the injection device (1, 100, 200) from an initial locked position to a second position whereby a needle penetration is performed, characterized in a plunger drive locking means arranged between the container driver and the plunger drive means providing a locking of the plunger drive means (50, 70) from being rotated in the initial locked position, and wherein the plunger drive locking means, when the container driver is moved to the second position, the plunger drive means (50, 70) are released such that due to an output torque from said first energy accumulating member, the plunger drive means (50, 70) are allowed to be rotated and the plunger rod is urged towards the proximal end of the injection device (1, 100, 200) whereby an injection is performed. - a housing (2, 3, 4, 5), - a container holder arranged movable in a longitudinal direction within said housing, said container holder being configured for accommodating a medicament container having a needle attached to one end thereof and a stopper sealingly and slidable arranged inside said medicament container at the other end thereof, - a plunger rod being arranged with a proximal end thereof contactable with said stopper, - a first and a second energy accumulating member arranged in the interior of the housing of the injection device (1, 100, 200) and adapted to accumulate and store energy, - plunger drive means (50, 70) being slidable arranged in relation to the plunger rod, being rotationally locked to the plunger rod and being rotatable in relation to the housing (2, 3, 4, 5), said plunger drive means (50, 70) being operationally associated with said first energy accumulating member, - a container driver attached to the container holder and threadedly connected to the plunger rod, said container driver being connected to said second energy accumulating member such that due to an output axial force from said second energy accumulating member, the container driver, the container holder and the plunger rod are axially moveable in relation to the housing (2, 3, 4, 5) a predetermined distance towards the proximal end of the injection device (1, 100, 200) from an initial locked position to a second position whereby a needle penetration is performed,