This optical fiber connection structure connects a multicore fiber and a bundle structure bundling a plurality of optical fibers. The multicore fiber has a plurality of cores arranged in a lattice. The bundle structure includes closely packed optical fibers of the same diameter. The bundle structure is configured such that signal light optical fiber groups including signal light optical fibers and a dummy fiber group including dummy optical fibers are stacked in multiple layers. The signal light optical fiber groups are configured with the signal light optical fibers aligned in the mutually contacting direction. The signal light optical fiber groups and the dummy fiber group are stacked orthogonal to the alignment direction of the optical fibers constituting the respective fiber groups.