Method for producing optical fiber

The invention provides a method for producing an optical fiber having low attenuation. The optical fiber includes a core that contains an alkali metal element. An optical fiber preform that includes a core part and a cladding part is drawn with a drawing apparatus to form an optical fiber, the core part having an average concentration of an alkali metal element of 5 atomic ppm or more. During the drawing, the time the temperature of glass is maintained at 1500 DEG C or higher is 110 minutes or less. The drawing speed is preferably 1200 m/min or more and more preferably 1500 m/min to 2300 m/min. The optical fiber preform preferably has a diameter of 70 mm to 170 mm and more preferably 90 mm to 150 mm.