PURPOSE: To provide a petroleum combustion burner whose size can be decreased, and whose capacity can be increased and in which the generation of NOx and Co can be lowered.

CONSTITUTION: A vaporizing chamber 10 is formed by providing an injection nozzle 5 and a flame holder 7 on the upstream side of a vaporing cylinder 1. Premix gas premixed in the vaporizing chamber 10 is burnt in a combustion chamber composed of a porous medium 11 through inflow holes 8 of the flame holder 7. This combustion causes a through pipe 3 on the downstream side of the combustion chamber and the flame holder 7 on the upstream side thereof to be heated. The combustion gas further heats a heat insulating material 12 provided on the downstream side and in contact with the through pipe 3 and is exhausted from an exhaust port 4. Therefore, a fluid flowing in the through pipe 3 cools the combustion chamber for a low-temperature combustion so that the generation of NOx and Co is suppressed. The surface area per unit volume in the combustion chamber is increased because of the porous medium 11, so that a combustion load factor can be improved. Thus, the compact burner and large capacity can be achieved.