The invention relates to a device for thermal waste gas treatment, in particular of oxidizable low-temperature carbonisation gases. Said device has at least two regenerators (45, 49) each with a heat accumulator (47, 51) and with a heating zone (53) arranged between said regenerators (45, 49). Waste gas to be treated can be supplied to a serial arrangement of at least two regenerators (45, 49) alternately from each side. A buffer cell (3) is provided to which essentially the uncleaned gas volume contained before change-over at the entrance of the relevant regenerator (45, 49), and the gas volume which is only partially cleaned can be conveyed each time the supply of waste gase is shifted to the respective other side of the serial arrangement. The uncleaned gas volume held in the buffer cell (3) after change-over or the gas volume which is only partially cleaned can be supplied completely until the next change-over to the respective other side of the serial arrangement of the regenerators. The invention also relates to a structurally simple embodiment of a buffer cell (3) for use with said device, which also reliably prevents the temperature from falling below dew point inside the buffer container (23).