Abstract: A method of manufacturing an elongated glass body by elongating a glass body of columnar or cylindrical shape. The method comprises: (1) a first elongating step for obtaining an intermediate elongated body, where the glass body is softened by heating and elongated, while the diameter of the softened part is measured, so that the measured value may become equal to a first controlled diameter which is larger than the target diameter, where the diameter of the intermediate elongated body satisfies the relationship at each position thereof: (the target diameter?10 ?m)<(the diameter of the intermediate elongated body)<(the target diameter+500 ?m); and (2) a second elongating step for obtaining an elongated glass body having the target diameter, where the intermediate elongated body is softened by heating and elongated.