Abstract: Provided relates to a contact force adjustment apparatus for a contact bar, which includes a height adjustment unit that varies a height of a dog detected by a photosensor, a tension checking unit capable of easily checking a change in tension for a spring, and a contact force adjustment unit including a dog protruding upward a support bar to rotate the support bar; a nut disposed on an upper surface of the support bar, and configured to support the dog when the dog rotates; a wedge member inserted into an insertion hole while being screw-fastened to an outer surface of the support bar, and having an upper portion with a diameter that is gradually increased upward along the height direction so that the wedge member is seated in the installation hole; and a height adjustment unit for adjusting a height of the dog.