Optical fiber drawing method and optical fiber drawing apparatus

An optical fiber drawing apparatus comprising:

• a drawing furnace which heats an optical fiber glass preform having a taper part in a state that the optical fiber glass is joined to a dummy rod;
• and
• a seal mechanism which obtains airtightness in an upper part of the drawing furnace,
• wherein the seal mechanism comprises a first seal part with which an outer peripheral surface of the optical fiber glass preform is sealed, and a second seal part arranged above the first seal part, the second seal part with which an outer peripheral surface of a sleeve member fixed so as to surround an outer periphery of the dummy rod is sealed, and
• wherein when a distance between a lower end of the sleeve member and the taper part of the optical fiber glass preform is set at E and a distance between the first seal part and the second seal part is set at D, “E≦D” is satisfied.