Apparatus for manufacturing optical fiber preform

An optical fiber preform manufacturing apparatus comprising a seal member, wherein

• the seal member is attached to a flange portion formed in an open portion of a reaction chamber into which a burner is inserted,
• the seal member includes:
• a first sheet that is flexible and includes an open portion that is smaller than an outer diameter of a cover for the burner, through which the cover is inserted;
• a second sheet having the same thickness as the first sheet and including an open portion that is larger than an outer diameter of the first sheet;
• and
• two third sheets that each include an open portion that is larger than the outer diameter of the cover for the burner and smaller than the outer diameter of the first sheet,
• the second sheet is arranged in the same plane as the first sheet without contacting the first sheet,
• the first sheet and the second sheet are sandwiched by the two third sheets, and
• the optical fiber preform manufacturing apparatus has the burner with the cover for the burner attached thereto inserted into the reaction chamber through the open portion of the seal member to generate and deposit glass microparticles.