Optical fiber base material manufacturing apparatus

A method of manufacturing an optical fiber base material using an optical fiber base material manufacturing apparatus that includes a reaction chamber, a burner, and a seal connection member, the method comprising:

• emitting a flame from the burner toward a starting member positioned inside the reaction chamber through a portion of the burner inserted into the reaction chamber through an insertion opening that creates a connection between the inside and outside of the reaction chamber, the portion surrounded by the seal connection member, which creates an air-tight seal between the burner and the reaction chamber at the insertion opening, wherein
• one end of the seal connection member firmly contacts the burner inserted therethrough,
• another end of the seal connection member firmly contacts the reaction chamber and has a through-hole formed therein through which the burner is inserted without contacting the seal connection member,
• the seal connection member includes a connecting portion that connects the one end to the another end, while preventing transfer of stress between the one end and the another end, and
• an inner diameter of the seal connection member decreases from the another end of the seal connection member to the one end of the seal connection member.