A method of fabricating a glass rod by feeding a first diameter glass preform into a furnace through a top portion of the furnace and drawing the glass preform from the furnace through a bottom portion of the furnace so that the first diameter glass preform is drawn into a second diameter glass rod, wherein the second diameter is smaller than the first diameter, comprising the steps of: controlling a feed speed and a drawing speed of the glass preform so that a ratio (V2/V1) between the feed speed and the drawing speed becomes a value ((D/d) 2) determined based on a diameter of the glass preform and a target diameter (d) of the glass rod; obtaining measured diameter data by measuring the diameter of the glass preform before being drawn at a plurality of positions along a longitudinal direction; acquiring the diameter of the glass preform for determining the ratio from the measured diameter data; and determining the feed speed so that the feed speed varies depending on a fluctuation of the measured diameter data in the longitudinal direction, wherein the step of acquiring the diameter of the glass preform comprises setting a diameter before being drawn and obtained from the measured diameter data as the diameter at a diameter acquisition position on the glass preform, the diameter acquisition position being away from a reference position of the furnace by a predetermined drawing reference distance on the glass preform and within a diameter decreasing region of the glass preform, wherein the drawing reference distance is defined by the formula L = VM/(π × (D/2) 2), wherein VM indicates a volume of a glass preform having a uniform diameter from a heater middle position to a position in the diameter decreasing region in the feeding direction, at the position the deformation rate is largest, and wherein the step of determining determines the feed speed so that the drawing reference distance is constant despite a fluctuation of measured diameter data in the longitudinal direction. controlling a feed speed and a drawing speed of the glass preform so that a ratio (V2/V1) between the feed speed and the drawing speed becomes a value ((D/d) 2) determined based on a diameter of the glass preform and a target diameter (d) of the glass rod; obtaining measured diameter data by measuring the diameter of the glass preform before being drawn at a plurality of positions along a longitudinal direction; acquiring the diameter of the glass preform for determining the ratio from the measured diameter data; and determining the feed speed so that the feed speed varies depending on a fluctuation of the measured diameter data in the longitudinal direction, wherein the step of acquiring the diameter of the glass preform comprises setting a diameter before being drawn and obtained from the measured diameter data as the diameter at a diameter acquisition position on the glass preform, the diameter acquisition position being away from a reference position of the furnace by a predetermined drawing reference distance on the glass preform and within a diameter decreasing region of the glass preform, wherein the drawing reference distance is defined by the formula L = VM/(π × (D/2) 2), wherein VM indicates a volume of a glass preform having a uniform diameter from a heater middle position to a position in the diameter decreasing region in the feeding direction, at the position the deformation rate is largest, and wherein the step of determining determines the feed speed so that the drawing reference distance is constant despite a fluctuation of measured diameter data in the longitudinal direction.