Optical fiber drawing furnace heating element, optical fiber drawing furnace, and method for manufacturing optical fiber

An optical fiber drawing furnace heating element comprising:

• a heat generator including:
• a tubular resistance heating element in which at least a part of an optical fiber preform is disposed in a through-hole;
• a first portion extending, from a first end portion of the heat generator, over a predetermined section along a longitudinal direction of the optical fiber drawing furnace heating element;
• and
• a second portion disposed closer to a second end portion of the heat generator than the first portion, wherein
• the second portion has a wall thickness on a side of the first end portion being equal to or larger than a wall thickness of the first portion, and
• the wall thickness of the second portion increases toward a side of the second end portion from the side of the first end portion.