Auto-injector for administering a dose of a liquid medicament, comprising: - an elongate outer casing arranged to contain a syringe with a hollow needle and a stopper for sealing the syringe and displacing the medicament, the outer casing 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 outer casing, - spring means capable of, upon activation: - pushing the needle from a covered position inside the outer casing 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 torsion spring grounded at one end (11.1) in the outer casing and at the other end in a first gear member rotatable about a longitudinal axis, wherein the first gear member, upon rotation, is arranged for translatively moving a second gear member toward the proximal end, the second gear member prevented from rotating and arranged to be coupled to the stopper in order to push it towards the proximal end, wherein the first gear member is engaged with the activating means prior to manual operation in a manner to prevent rotation and disengaged from the activating means upon manual operation, wherein at least one skin contact trigger element (17.2) is arranged at the proximal end of the outer case, the skin contact trigger element (17.2) translatable in longitudinal direction between a proximal position and a distal position and biased in proximal direction in a manner to protrude from the outer casing in the proximal position, wherein in its proximal position the skin contact trigger element (17.2) is arranged to prevent the spring means from being released. and wherein the skin contact trigger element (17.2) in its distal position is arranged to allow release of the spring means. - an elongate outer casing arranged to contain a syringe with a hollow needle and a stopper for sealing the syringe and displacing the medicament, the outer casing 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 outer casing, - spring means capable of, upon activation: - pushing the needle from a covered position inside the outer casing 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 outer casing 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 torsion spring grounded at one end (11.1) in the outer casing and at the other end in a first gear member rotatable about a longitudinal axis, wherein the first gear member, upon rotation, is arranged for translatively moving a second gear member toward the proximal end, the second gear member prevented from rotating and arranged to be coupled to the stopper in order to push it towards the proximal end, wherein the first gear member is engaged with the activating means prior to manual operation in a manner to prevent rotation and disengaged from the activating means upon manual operation, wherein at least one skin contact trigger element (17.2) is arranged at the proximal end of the outer case, the skin contact trigger element (17.2) translatable in longitudinal direction between a proximal position and a distal position and biased in proximal direction in a manner to protrude from the outer casing in the proximal position, wherein in its proximal position the skin contact trigger element (17.2) is arranged to prevent the spring means from being released. and wherein the skin contact trigger element (17.2) in its distal position is arranged to allow release of the spring means.