The invention relates to a single-use injector comprising a housing (200) accommodating a mechanical spring energy reservoir (50), a cylinder/piston unit (100), a piston-actuating ram (60) and a trigger unit (80), the spring-loaded piston-actuating ram being releasably supported on the housing. The housing of the injector consists of a thin-walled sheet metal part (201). Said sheet metal part has at least two limbs (20). Each limb has a bent retaining element (221) or a recess on its free end. The limbs are elastic flexural beams the center sections of which are bent in the shape of a z or an s to define a supporting section (231) for the piston-actuating ram. The contact zone between an individual supporting section and the piston-actuating rod represents a wedge gear pairing that forces the respective limb outwards.
