An amorphous carbon film forming method is performed by using a parallel plate type plasma CVD apparatus in which an upper electrode and a lower electrode are installed within a processing chamber, and the method includes: disposing a substrate on the lower electrode; supplying carbon monoxide and an inert gas into the processing chamber; decomposing the carbon monoxide by applying a high frequency power to at least the upper electrode and generating plasma; and depositing amorphous carbon on the substrate. It is desirable that the upper electrode is a carbon electrode.