Cutting and planarization of diamond films have been performed using copper vapor laser under air at-mosphere. Diamond films of about 350${mu}{ extrm}{m}$ and 800 ${mu}{ extrm}{m}$ thick have been synthesized with DC plasma assisted chemical vapor deposition. The position of a specimen has been controlled by computer-driven stage. With copper vapor laser beam of 7W cutting depth increases rapidly and saturates with increasing scan number and decreasing scan speed. 8 repetitive scans at scan speed 0.5 mm/sec produce the maximum cutting depth without focus shifting Rod-shape copper vapor laser beam can be made and used effectively in planar-ization of rough diamond surface.