Abstract: The invention relates to a combustion device for wood or coal comprising a front wall with a fuel charging opening, two side walls, a rear wall, a bottom wall, a top wall, a door for the fuel charging opening, a control element for controlling a fresh-air inlet opening, an inner dividing wall which divides the interior of the device into a pre-combustion chamber and a post-combustion chamber, and a passage opening between the two chambers and a grating at the bottom of the pre-combustion chamber and a flue gas discharge opening; the dividing wall is horizontally disposed and a shaft pipe surrounded by an annular chamber which is in communication with the fresh-air inlet opening is inserted sealingly into its passage opening; the grating is placed on its upper end.