Auto-injector for administering a dose of a liquid medicament, comprising: - an elongate housing arranged to contain a syringe with a hollow needle and a stopper for sealing the syringe and displacing the medicament, the housing having a distal end and a proximal end with an orifice intended to be applied against an injection site, wherein the syringe is slidably arranged with respect to the housing, - spring means capable of, upon activation: - pushing the needle from a covered position inside the housing into an advanced position through the orifice and past the proximal end, - operating the syringe to supply the dose of medicament, and - retracting the syringe with the needle into the covered position after delivering the medicament, - activating means arranged to lock the spring means in a pressurized state prior to manual operation and capable of, upon manual operation, releasing the spring means for injection, wherein the spring means is a single drive spring in the shape of a compression spring arranged to be grounded at a distal end in the housing for advancing the needle and for injecting the dose of medicament via a plunger and wherein the drive spring is arranged to have its ground in the housing switched to its proximal end for retracting the syringe, wherein a retraction sleeve is axially movable arranged in the housing, wherein the drive spring is arranged inside the retraction sleeve with its distal end bearing against a distal end face and with its proximal end bearing against a thrust face of a decoupling member, wherein at least one resilient decoupling arm is arranged at the decoupling member, the decoupling arm arranged for bearing against a first shoulder of the plunger in proximal direction, characterized in that the resilient decoupling arm is supportable by an inner wall of the retraction sleeve in order to prevent the decoupling arm from being flexed outward and slip past the first shoulder and wherein at least one aperture is arranged in the retraction sleeve allowing the decoupling arms to be flexed outward by the first shoulder thus allowing the first shoulder to slip past the decoupling arm in proximal direction, wherein the aperture extends at least almost to the position of the decoupling arms in the as delivered state, wherein the aperture is arranged to be angularly misaligned with respect to the decoupling arm when the retraction sleeve is in its proximal position and wherein the aperture is arranged to rotate so as to align with the decoupling arms upon translation of the retraction sleeve out of the proximal position in distal direction. - an elongate housing arranged to contain a syringe with a hollow needle and a stopper for sealing the syringe and displacing the medicament, the housing having a distal end and a proximal end with an orifice intended to be applied against an injection site, wherein the syringe is slidably arranged with respect to the housing, - spring means capable of, upon activation: - pushing the needle from a covered position inside the housing into an advanced position through the orifice and past the proximal end, - operating the syringe to supply the dose of medicament, and - retracting the syringe with the needle into the covered position after delivering the medicament, - pushing the needle from a covered position inside the housing into an advanced position through the orifice and past the proximal end, - operating the syringe to supply the dose of medicament, and - retracting the syringe with the needle into the covered position after delivering the medicament, - activating means arranged to lock the spring means in a pressurized state prior to manual operation and capable of, upon manual operation, releasing the spring means for injection,