Abstract: A hair cutting device has a movable arm for holding a comb and a mechanism for driving the movable comb which combines light weight with hardness. The mechanism to drive the movable arm comprises a bar screw rotated by a drive motor and a ring that ascends or descends, in accordance with the spiral groove of the bar screw. To eliminate hair damage caused by a haircut, high-frequency electricity or minute flame jets from minute holes can be alternatively used for cutting or burning off hairs nipped in the comb.