An oxygen chemical generation respiration apparatus of the cartridge type intended to receive an absorbing mass in the form of pellets such as potassium superoxide pellets, is provided with a central connector (5) for intake of the gases to be purified, vertically extended as an intake conduit (5') to a clearance space (9) above the housing bottom at the level of a lower perforated wall (7) supporting the regenerating charge, this conduit coming out in the center of this wall to which it is fastened; the upper part (6) of the cartridge housing, on the output side of the gases to be treated, is provided with a series of radiators (11) parallel to the direction of circulation of the gas flows in the regenerating charge, fastened to the housing walls (12) and whose length is less than the spacing between the two walls (7) and (8).