A mask manufacturing apparatus includes a chamber, a laser beam irradiator, a stage, a cooling system, and a fan. The chamber provides an interior space therein. At least an upper wall of the chamber comprises a glass. The laser beam irradiator is disposed outside the chamber and configured to divide a laser beam into a plurality of sub-laser beams to irradiate the sub-laser beams onto a shadow mask material. The stage is disposed in the chamber and the shadow mask material is placed on the stage. The cooling system is configured cool the interior space. The fan configured to discharge heat generated in the interior space of the chamber to the outside of the chamber. Therefore, the shadow mask may be protected from overheating.