To provide a mounting structure for a radiant tube 1 for preventing the fall of the radiant tube 1 off a sleeve 2 even when joint strength between the radiant tube 1 and the sleeve 2 lowers, and to provide a radiant tube burner.

The radiant tube burner comprises the ceramics radiant tube 1 exposed to the inside of a furnace and having a combustion chamber formed inside and a holding part 6 fixed to a furnace wall for holding the radiant tube 1. The cylindrical sleeve is fixed to the holding part 6 to externally encircle the radiant tube 1 at its outer face on the rear end side via an adhesive layer 4 filled with adhesive. The inner diameter at the front end of the sleeve 2 is smaller than the outer diameter at the rear end of the radiant tube 1.