A method for manufacturing an optical fiber includes: a coating step of forming a first layer by applying a first ultraviolet ray curable resin composition onto a glass fiber, and then, of forming a second layer by applying a second ultraviolet ray curable resin composition onto the first layer; a first irradiation step of curing the first layer and the second layer by irradiating the first layer and the second layer with an ultraviolet ray, and of obtaining the optical fiber including a primary resin layer and a secondary resin layer; and a second irradiation step of irradiating the optical fiber with an ultraviolet ray at an illuminance of less than or equal to one tenth of an illuminance in the first irradiation step for an irradiation time of longer than or equal to 10 times an irradiation time in the first irradiation step.