Device for reburning furnace combustion products is arranged above a combustion unit in the form of a hollow body with a bottom inlet hole and a top outlet hole, on the side wall of which hollow body there is formed a horizontal row of evenly distributed air holes, wherein, rectangular protrusions are formed to the right- and left-hand sides of each air hole on the inside of the body of the device said rectangular protrusions serving to feed supplementary air, which comes in via the air holes, from the outer holes of the furnace into the body of the device, providing for accelerated incineration of residual combustion products without formation of a vortex in the airflow.