The invention relates to a low nitrogen oxide heat accumulating type flat burner, and relates to the field of heat treatment fuel industrial furnaces. A heat accumulating body is installed in a vertical shell, an air inlet is formed in the top of the heat accumulating body, a vertical ventilation hole below the heat accumulating body communicates with a horizontal ventilation hole, and the other end of the horizontal ventilation hole is provided with a spraying nozzle of a horn-shaped gradually-widening structure; an air rotational flow device is installed at the connecting position of the vertical ventilation hole and the horizontal ventilation hole, a natural gas pipe is coaxially installed in the horizontal ventilation hole, one end of the natural gas pipe penetrates a shell to be connected with a natural gas inlet, the other end of the natural gas pipe extends out of the spraying nozzle, a plurality of guide blades are installed in the positions, at one end of the natural gas inlet, in the natural gas pipe at intervals and are fixed through a center shaft, and a plurality of layers of natural gas spraying openings are formed in the positions, at one end of the spraying nozzle,of the pipe wall of the natural gas pipe in the tangential direction at intervals. The burner is small in size, large in power, less in nitrogen oxide emission, good in energy-saving effect and convenient to install.