PURPOSE: To form a column-like flame favorably over a wide range irrespective of any change in a mixing air ratio, by improving a gas spouting passageway in its configuration.

CONSTITUTION: A burner caster section 4 is provided, the section 4 comprising a spousing passageway R for spousing a mixed gas from a mixing section 3 in a column-like configuration, the passageway R being provided in series with the mixing section 3 having a fuel gas feed port 1 and an intake port 2 for a burning air. Thus, a toroidal flame burner is provided for spousing a column-like flame. Furthermore, a mixed gas flowed from the mixing section 3 in a turbulent flow condition is further flowed at a first passageway section R1 in an equivalent diameter state, whereby making consistent the turbulent flow of mixed gas flowed from the mixing section to the burner caster section. Therefore, the flow is enlarged in diameter at a second passageway section R2 for thereby reducing its turbulent force. Moreover, the diameter enlargement of flow is restricted at a third passageway section R3 and flowed in an equivalent diameter state for subsequential spousing. Thus, a column-like flame can be obtained consistently.