Abstract: This invention concerns an improved combustion chamber comprising two concentric sheet metal cases forming a space into which air is admitted. The air passes from the space to the interior of the chamber in primary, secondary, annular, and tertiary air flows. The fuel coming from lateral nozzles forms a flame which is directed at first toward the closed end, then turned back by the secondary air flow. The external case comprises two walls between which a cooling flow circulates. The invention thereby achieves reduction in atmospheric pollution from exhaust gases.