PURPOSE: A surface treatment unit for minimizing damage to a steel wire is provided to prevent the breakage of a steel wire by minimizing an elastic rebound force. CONSTITUTION: A surface treatment unit comprises first and second steel wire brushes(12,14), a supporting tube(16), and a molding material. The first steel wire brush comprises an insertion part and a vertical part. The insertion part surrounds the external diameter of a fixed axis. The vertical part forms a rough surface on a work surface. The insertion part surrounds the outer circumference of the first steel wire brushes. The supporting tube surrounds the outside of the insertion part of the second steel wire brush. The molding material fixes the insertion part of the first and second steel wire brushes through the cut-out of the supporting tube.
