Provided is an apparatus for manufacturing an optical fiber Bragg grating. The optical fiber Bragg grating manufacturing apparatus includes: an optical fiber; a laser for irradiating a laser beam to the optical fiber to change a refractive index of a core of the optical fiber; an optical system for periodically changing the intensity of the laser beam irradiated to the optical fiber core; a broadband light source for providing broadband light as an incident signal to the optical fiber in order to observe a reflection characteristic of a Bragg grating formed in the optical fiber by the laser beam converted by the optical system; and an optical spectrum analyzer (OSA) for measuring a reflected signal or a transmitted signal of the broadband light incident to the Bragg grating, wherein the optical system realizes a Bragg wavelength (λB) in order to periodically change the refractive index of the optical fiber core, and the broadband light source and the optical spectrum analyzer use λB/N, where λB denotes the Bragg wavelength and N is a natural number which is equal to or more than 2.