The invention relates to an injection apparatus for needle-free injection of amedium. Theinjection apparatus comprises an injector device and an ampoule unit. Theampoule unitcomprises a base body for storing the medium to be injected, and a jacket thatexerts compressiveforces upon the base body, wherein a nozzle is provided at a longitudinal-axisend of the ampouleunit. The jacket completely surrounds the base body along the longitudinalaxial direction andpartially surrounds the nozzle. The compressive forces of the jacket at leastcounterbalance theinternal stresses generated during the manufacture of the base body. A plungerrod is provided ata longitudinal-axis end of the ampoule unit opposite the nozzle. The plungerrod is hollow andafter the ampoule unit has been filled with the medium, the plunger rod issqueezed in at leastone spot.
