To reduce generation of an NOx even in case of a combustion in an inner tube by slowly mixing combustion air and fuel gas injected from a nozzle hole in a radial direction, and slowly conducting a combustion, thereby suppressing generation of a high temperature part.

In the high temperature regenerator, a fuel supply tube 10 is disposed at a central axis of the low NOx burner, and an air passage is constituted at its outer periphery. A flame stabilizing plate 12 is provided at an end side of the tube, and many holes 13C for passing combustion air are formed at the plate 12. A nozzle hole 14 for injecting fuel gas in a radial direction at a downstream side of the plate is provided at the tube. The burner of the constitution that no hole is provided at a position corresponding to an injecting direction of fuel gas from the hole 14 is provided at the stabilizing plate. Thus, a CO can be reduced together with the NOx.