PURPOSE: To remove a vapor flux residue completely and enable to conduct a satisfactory brazing operation for a long period of time by a methood wherein a stream of a high-pressure gas is jetted to flame holes of a burner to remove the vapor flux residue deposited or grown on the peripheral edges of the flame holes.

CONSTITUTION: A nozzle 5 for jetting an incombustible high-pressure gas, for example, argon gas and a gas supplying pipe 6 are provided so that the nozzle 5 is faced skewly to the front face 4 of a burner main body 3 at which the flame holes 2 are opened. The high-pressure gas from the nozzle 5 is jetted against the flame holes 2 to clean the peripheral edges of the flame holes 2, whereby the vapor flux residue formed at the peripheries of the flame holes 2 can be completely removed while maintaining an operative condition. Accordingly, the shape of flames 7 can be maintained in the desired state and satisfactory automatic brazing operation can be accomplished for a long period of time.