Hard disk drives are mass-produced as the secondary storage devices of computer systems. A thin-film magnetic head, one of the major components of the drive, consists of a head and a slider. The slider must be lifted 20 nm above the recording surface by the effect of air flow caused by the rotating magnetic medium, in order to avoid contact with the magnetic medium and the head. To maintain the small amount of lift, the air-bearing surface facing the magnetic medium of the slider needs requires finishing to a flat or toric surface at nanoscale accuracy. We have developed an accurate and controllable process for nano-crowning using a YAG laser, solving problems found in the conventional process. The new process has been applied to the magnetic head crowning device for mass production of hard disks.