This optical fiber (1A) is provided with an incident end to which light is incident and an emitting end from which light is emitted, and also provided with an aperture formed by the irradiating the core (4) at or near the emitting end with an ultrashort pulsed laser having a pulse width of 10-15 to 10-11 seconds. This aperture is configured from a light scattering region formed by inducing damage change in a portion of the aforementioned core through irradiation with the ultrashort pulsed laser, a light absorption region formed by inducing blackening in a portion of the aforementioned core through irradiation with the ultrashort pulsed laser, or a volume diffractive optical element formed by inducing a refractive index change in a portion of the aforementioned core through irradiation with the ultrashort pulsed laser. The beam control properties of the light emitted from the emitting end are improved by means of adding this aperture function to the aforementioned optical fiber.