I/We Claim:
1. An optical fiber unit comprising:
a plurality of optical fibers; and
at least two binding materials that bind the plurality of optical fibers,
wherein the two binding materials are wound around the plurality of optical fibers in an SZ shape, and are adhered to each other at respective reversed portions to form an adhesive part,
wherein the adhesive part extends along a longitudinal direction in which the optical fiber unit extends, and
wherein when a length of the adhesive part in the longitudinal direction is L, and a binding pitch of the binding material in the longitudinal direction is P,
0.15 < L/(P/2) < 0.8 is satisfied.
2. The optical fiber unit according to claim 1,
wherein a center line of the binding material has a linear portion extending along the longitudinal direction, and
wherein the linear portion is included in the adhesive part.
3. The optical fiber unit according to claim 2,
wherein the linear portions of the center lines of the two binding materials overlap each other at the adhesive part.
4. The optical fiber unit according to claim 1 or 2,

wherein the center lines of the two binding materials intersect each other at the reversed portions to form a plurality of intersection points.
5. The optical fiber unit according to any one of claims 1 to 4,
wherein an adhesive strength of the adhesive part is 12.5 gf or more and 91.0 gf or less.
6. An optical fiber cable comprising:
the optical fiber unit according to any one of claims 1 to 5, and a sheath that covers the optical fiber unit.