For an optical recording medium having a phase change type recording layer on it's a substrate and having as read only area and a writable area in a recording area, a data recording method is provided which records data in the writable area. This data recording method comprises a transfer step of transferring program data recorded in the read only area in a practical form to an external computer, and an execution step (step A10) of automatically executing the program data in the external computer to record data in the writable area, which can facilitate manufacturing and reduce the possible of destruction or falsification of ROM data.