Two functions of Ni in the process of graphite thin-film formation from organic materials by chemical vapor deposition (CVD) were studied. When dehydrogenation of a certain organic material was enhanced by Ni during CVD at 600 and 700 degrees C, the graphite thin film could be formed on Ni at these temperatures. On the other hand, a lot of organic materials changed into graphite by CVD on Ni above 800 degrees C, which corresponds to the obtained result that Ni deposited on disordered graphite changed the disordered graphite to crystalline one by heat treatment above 800 degrees C.