An object of the invention is to improve polarization dependence of insertion loss (PDL) in an ultraviolet light induced optical fiber grating. In the invention, in a method of manufacturing an optical fiber grating with a plurality of grating sections arranged intermittently at a predetermined period along the longitudinal direction, by irradiating, from the side of an optical fiber having locations made of a material wherein the refractive index rises when irradiated by light of a specific wavelength, light of this specific wavelength along the length direction of the optical fiber at a predetermined period, causing the refractive index of the irradiated sections to rise, high refractive index sections are formed by irradiating light evenly onto the optical fiber around the circumferential direction thereof.