An optical fiber unit for air blown installation includes at least one optical fiber having a core layer and a clad layer, a protective layer coated on the surface of the optical fiber; and protrusions made of polymer resin and formed on the outer circumference of the protective layer in a banded shape. The protrusions may be formed either by supplying polymer resin to the outer circumference of the optical fiber with passing the optical fiber through an extrusion dice in which grooves of a predetermined shape are formed on a hollow inner circumference thereof, or by supplying polymer resin to the outer circumference of the optical fiber through nozzles with moving the optical fiber in a longitudinal direction.