The invention refers to an auto-injector for administering a dose of a liquid medicament (M), the auto-injector having a distal end (P) and a proximal end (D) with an orifice intended to be applied against an injection site and comprising:an elongate housing arranged to contain a syringe with a hollow needle and a stopper for sealing the syringe and displacing the medicament (M), wherein the syringe (3) is slidably arranged with respect to the housing,a drive means capable of, upon activation: pushing the needle from a retracted position into an advanced position through the orifice and past the proximal end (P), andoperating the syringe to supply the dose of medicament (M),a plunger for transmitting power from the drive means to the syringe and/or stopper,activating means arranged to lock the drive means in a compressed state prior to manual operation and capable of, upon manual operation, releasing the drive means for injection,characterized in that translation of the needle and the syringe and/or translation of the plunger in longitudinal direction is controlled by at least one ramp or one thread so as to cause the syringe and/or the plunger to rotate when translated at least during part of the translation.
