Abstract: A small combustion apparatus for domestic or commercial use, wherein the quantity of combustion is increased by enhancing the mounting density of the burner units and to stabilize combustion using a lean fuel mixture resulting in a decreased generation of nitrogen oxides and noise. The burner has first and second burner units, arranged alternatively adjacently to one another. Each of the burner units has a flame port portion at the top of the burner body vertical and flat, has an inlet for fuel gas and air at the bottom of the burner body, has a mixing channel extending from the inlet to the flame port portion; and has inlets of the first burner units located below the inlets of the second burner units fuel gas spouts, are provided to correspond to the respective inlets of the first and second burner units.