An optical fiber base material machining method for forming spindle-shaped portions at ends of the optical fiber base material by severing the optical fiber base material after reducing an outer diameter of the optical fiber base material to a predetermined target outer diameter at a predetermined machining position, comprising: reducing the outer diameter to a predetermined intermediate outer diameter between the outer diameter before the machining and the target outer diameter at the machining position; flame polishing a surface of the optical fiber base material in a region including the machining position; and further reducing the outer diameter of the optical fiber base material.