The invention relates to a disposable injector with a housing (10) in which arearranged at least one mechanical spring energy reservoir (50), at least one cylinder/pistonunit (100), at least one piston-actuating ram, and at least one trigger unit.The spring-loaded piston-actuating ram is supported on the housing via at leastone support rod (21), wherein the contact zone located between an individualsupport rod and the piston-actuating ram represents a wedge gear pairing thatforces the respective support rod radially outwards. The support rod or supportrods bear on at least one trigger element (82) that is mounted on the housing andpositioned in a locking position. The trigger element can be brought by displacementinto a triggering position that releases the piston-actuating ram.
