Described is an auto-injector for administering a medicament comprising a case arranged to receive a packaged syringe comprising an injection needle, wherein the case comprises a front case rotatably coupled to a rear case, and a drive spring arranged to advance a plunger relative to the packaged syringe, and a reset mechanism for the drive spring arranged to retract the plunger and compress the drive spring when the front case is rotated relative to the rear case.