To prevent a band which is wound on electric wires for fastening from rotating and skidding relative to the electric wires.

On both side edges, left and right, in width direction of a band inner surface which is to be an inner peripheral side that contacts to electric wires under such condition as a band is wound on the electric wires, a gap that is a deep groove is opened so that a rail part is protruded along length direction at a predetermined pitch. The rail part consists of a high protruding part and a low protruding part, being provided alternately. The band has such configuration as the high protrusion part and the low protrusion part bend to form a polygon with the deep groove as a support point.