Injection device, comprising: shell, the shell are arranged to comprising drug cartridge Needle holder keeps injection needle The needle sleeve of generic tubular, the needle sleeve are fixed relative to the needle holder, and can be moved in the axial direction relative to the shell And gear assembly, the gear assembly includes the rotation gear for being fixed to the needle holder, the second rack gear of the first rack gear being arranged in the needle sleeve and arrangement on the housing, wherein the gear assembly is arranged so that needle sleeve causes movement of the needle holder on proximal axis direction in the movement on proximal axis direction.
