Abstract: The fire extinguishing apparatus for oxy-acetylene welding assemblies having a cylinder having a free floating piston, over the actuator of a release valve, mountable at one end of a pressurized bottle containing a fire extinguishing fluid and connectable at its opposite end to an oxygen return line and a valve assembly connectable between the oxygen line and the torch, the valve assembly has a through passage for enabling passage of oxygen from the oxygen line to the torch and an intersecting passage having a manually operated shut-off valve intersecting the through passage at one end and having means at its opposite end for connection to the oxygen return line to the bottle of extinguishing fluid for enabling pressurized oxygen to flow to the cylinder and move the piston into operating engagement with the actuator of the release valve so as to release the fire extinguishing fluid therefrom. A discharge hose is extended from the fire extinguishing fluid bottle to the operator of the welding torch.