Patent ID: 8312744

Claim:
A burner for producing glass fine particles, comprising: a glass material gas discharge tube; a combustible gas discharge tube that is provided so as to surround the glass material gas discharge tube, a center of the combustible gas discharge tube being positioned on a center of the glass material gas discharge tube; and a plurality of oxidizing gas discharge tubes that are provided within the combustible gas discharge tube such that ports of the oxidizing gas discharge tubes are provided in one or more concentric circles with respect to a port of the glass material gas discharge tube, wherein the ports of the oxidizing gas discharge tubes in a same circle have a same focus length, each of the plurality of oxidizing gas discharge tubes has: a gas introducing portion at which the oxidizing gas discharge tube branches from a common main tube; and a fastening portion that is positioned between the gas introducing portion and an end of the oxidizing gas discharge tube that is opposite to the gas introducing portion, and D 1 >D 3 and D 2 >D 3 where D 1 denotes an inner diameter of each of the plurality of oxidizing gas discharge tubes at the fastening portion, D 2 denotes an inner diameter of each of the plurality of oxidizing gas discharge tubes at the gas introducing portion, and D 3 denotes a maximum inner diameter of each of the plurality of oxidizing gas discharge tubes at portions other than the fastening portion and the gas introducing portion.