PURPOSE: To improve heating efficiency in a blast burner to heat an elongated object in a furnace, by forming a flat shortlength flame emitted from the burner according to a shape of the object to be heated.

CONSTITUTION: A combustion chamber 3 having a slotted opening at its end is formed in a burner tile 1, a gas piping 4 is inserted from a rear side thereof and a manifold 4' having a Tshaped end is disposed at the base portion in the combustion chamber 3. A gas exhaust orifices 5 are pierced on the manifold 4' and a primary air exhaust orifices 6 are formed on both sides of the manifold 4' to blast primary air to gas emitting from the exhaust orifices 5 so as to produce a gas/air mixture to be burned, In addition, a portion of compressed air in an air chamber 7 is emitted, as secondary air, from a secondary exhaust orifices 10 along an inside wall of the combustion chamber 3. Thus, complete combustion flame is emitted from the orifices 2 to form a flat short-length flame. The burner is fitted by means of a bracket 11 onto a furnace wall and the burner tile 1 is inserted into a furnace.