The fixing apparatus 1 is comprised of a pressure fixing device 13 for freely pressure fixing the rod portion 7R to a circular arc rod engagement portion 9 freely engaging with the rod portion 7R, and small protruding portions 15, 15 eating into the rod portion 7R and having an acute angle in both end sides of the rod engagement portion 9 outside the pressure fixing device 13. Further, a recess surface 9A of the rod engagement portion 9 between the small protruding portions 15, 15 provided in the rod engagement portion 9 is formed as a rough surface.
