A housing of the injector is made from a thin-walled sheet-metal part. The sheet-metal part has at least two branches or legs. Each branch has, at the free end thereof, an angled retaining element or a recess as a means of receiving the cylinder of a cylinder/piston unit. The branches are elastic flexural beams which, in the middle area, are each bent in a Z-shape or S-shape to form a supporting portion for the piston-actuating ram. The contact zone situated between an individual supporting portion and the piston-actuating ram represents a wedge gear pairing that forces the respective branch outwards. The trigger unit comprises at least a trigger element which is slidably supported on the metal sheet, wherein the support section or, respectively the contact sections extend outwardly into longitudinal grooves. The branches may be provided with a locking tongue to engage corresponding openings in the trigger element to lock the housing in position as desired.
