A method of manufacturing an optical fiber of the invention includes: preparing a direction changer; drawing the bare optical fiber from an optical fiber preform; providing a coated layer on a periphery of the bare optical fiber; obtaining an optical fiber by curing the coated layer; changing a direction of the bare optical fiber at a position between a bare-optical-fiber formation position and a coated-layer provision position; and measuring the outer diameter of the coated layer; and adjusting the length of the bare optical fiber from a drawing unit to a coating unit by controlling a position of the direction changer based on a measurement value of the outer diameter, the drawing unit forming the bare optical fiber, the coating unit providing the coated layer on the periphery of the bare optical fiber.