A burner is provided for a furnace having at least one windbox that is supplied with air for combustion and has extending therethrough at least one such burner, which opens out toward the combustion chamber. The burner has at least one primary air channel, which is supplied from the outside with a coal dust/air mixture, at least one secondary air channel, which surrounds the primary air channel, and at least one tertiary air channel, which surrounds the secondary air channel. The secondary and tertiary air channels can be supplied with air from the windbox in a regulated manner. Along a rotationally symmetrical portion of an outer surface of each of the secondary and tertiary air channels there is respectively provided at least one air inlet opening. Respective annular valve sections are rotatably disposed about one of the rotationally symmetrical portions of the secondary and tertiary air channels. These two annular valve sections each have at least one air passage opening, and are successively disposed one after the other as viewed in an axial direction of the burner.