Abstract: The invention relates to an injection device including a tubular casing for a reservoir (ampoule) for a medicinal fluid, an injection needle, and a needle protecting sleeve which may be axially shifted on the casing between a protective position in which it surrounds the injection needle and a functional position in which it exposes the injection needle, wherein, in the protective position, the distal end of the needle protecting sleeve axially abuts at least one stopper and, in order to release the sleeve, the at least one stopper is radially shifted by applying a force to the casing.