An optical fiber unit includes: a plurality of optical fibers; and at least two binding materials that bind the plurality of optical fibers. The two binding materials are wound around the plurality of optical fibers in an SZ shape and adhered to each other at reversed portions of the SZ shape to form an adhesive part. The adhesive part extends along a longitudinal direction where the optical fiber unit extends, and 0.15≤L/(P/2)≤0.8 is satisfied where L is a length of the adhesive part in the longitudinal direction and P is a binding pitch of the two binding materials in the longitudinal direction.