The invention relates to an injection device including an injector and an ampoule unit for the needle-free injection of a medium. A needle-free injection device has a first chamber with an interior that opens into a nozzle, and has a second chamber with an interior that is separated from the interior of the first chamber. The interiors of the two chambers are connectable to each other, thus allowing a mixing and/or reaction of the media located in the chambers. In the first chamber, a powdery medium can be accommodated, and in the second chamber, a fluid medium is can be accommodated. The fluid medium can be transported into the first chamber for the mixing/reaction of the two media.
