A distributed optical fiber vibration measurement device, wherein the distributed optical fiber vibration measurement device is provided with: a phase-constant difference calculation means for determining a phase constant difference from two alternating-current components obtained by causing a first test light pulse to be incident on each of a plurality of integrated optical fibers to be tested and causing first backscattered light generated at the sites of the plurality of optical fibers to be tested to interfere with other light having an optical frequency different from the optical frequency of the first test light pulse; a phase distribution data creation means for comparing the amplitudes of each of the two alternating-current components obtained by causing the first backscattered light generated at the sites of the plurality of optical fibers to be tested to interfere with the other light, selecting phase data of the alternating-current component having the greater amplitude at the sites, and creating temporally arranged phase distribution data; and a vibration measurement means for measuring vibration in an optical fiber to be tested, by specifying the difference in optical path length between any two sites of the optical fiber to be tested from the phase constant difference and the phase distribution data.
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