Abstract: In a fire extinguisher comprising a container containing extinguishing agent and a holder for a propellent gas cartridge as well as an actuating mechanism, arranged between an actuating member (46) and a valve pin (22) of a valve controlling the release of the extinguishing agent which is acted upon by the propellent gas is a wedge-shaped safety element (48) so that when the safety element is withdrawn a propellent gas cartridge (18) is opened automatically by a push rod (24) disposed on the valve pin. This ensures that the container containing the extinguishing agent is acted upon by the propellent gas from the propellent gas cartridge (18) before the fire extinguisher is first actuated.