An apparatus for manufacturing a display device includes a mask assembly arranged inside a chamber and facing a display substrate, a magnetic force portion arranged inside the chamber and applying a magnetic force to the mask assembly, and a deposition source which is arranged inside the chamber, faces the mask assembly, and supplies a deposition material that passes through the mask assembly and is deposited on the display substrate. The mask assembly includes a first mask layer including a first mask opening, and a second mask layer disposed on the first mask layer. The second mask layer includes a metal layer including a metal opening corresponding to the first mask opening, and an inorganic layer including an inorganic opening corresponding to the first mask opening and the metal opening. In a plan view, a width of the metal opening is greater than a width of the inorganic opening.