Method and facility for producing optical fiber base material

A method for manufacturing an optical fiber preform including a core part and a clad part using a manufacturing facility provided with at least three burners, the method comprising:

• a core part deposition process of, while relatively moving the burners and a first target material in a first reciprocating motion, depositing core glass particles generated in a flame formed by the burners on the first target material;
• and
• a clad part deposition process of, while relatively moving the burners and a second target material including the core part obtained through the core part deposition process in a second reciprocating motion, depositing clad glass particles generated in the flame formed by the burners on the core part, wherein
• the number of the burners used in the core part deposition process is less than the number of the burners used in the clad part deposition process,
• a distance between turning back points in the first reciprocating motion is equal to or greater than a length of an effective portion of the optical fiber preform,
• at least three burners are used in the clad part deposition process,
• a distance between turning back points in the second reciprocating motion is shorter than the distance between the turning back points in the first reciprocating motion, and
• the turning back points in the second reciprocating motion vary during the clad part deposition process.