An optical measuring device and a fiber bundle association method, capable of associating positions of respective optical fibers of a fiber bundle with a simple configuration, are provided. An optical measuring device 1 includes an association unit which, when light having an intensity gradient around an illumination fiber 341 is projected to an end face of a distal end portion 33 of a measurement probe 3, associates the respective signal intensities of light-receiving fibers 342 detected by a detection unit 24, with distances from the illumination fiber 341 to the respective light-receiving fibers 342 on the end face of the distal end portion 33 of the measurement probe 3.
