A deposition mask apparatus , comprising: a frame including a first portion , a second portion facing the first portion across an opening in a first direction (D1), a third portion , and a fourth portion facing the third portion across the opening in a second direction (D2) different from the first direction (D1), and including a first surface and a second surface that is located opposite to the first surface ; a supporter including a plurality of supporting members that are arranged in the second direction, the supporting member including a first end that is fixed to the first portion on the first surface side and a second end that is fixed to the second portion on the first surface side; and a deposition mask including a third end that is fixed to the third portion on the first surface side and a fourth end that is fixed to the fourth portion on the first surface side, and including a plurality of holes that are located between the third end and the fourth end , wherein the plurality of supporting members include at least a first supporting member that is closest to an intermediate position between the third portion and the fourth portion of the frame and a second supporting member that is located closer to the third portion of the frame than the first supporting member , and when the first surface of the frame is located above the second surface , the first supporting member in a state of warping downward from the frame with a first warping amount (a1) supports the deposition mask from below, and the second supporting member in a state of warping downward from the frame with a second warping amount (a2) that is smaller than the first warping amount (a1) supports the deposition mask from below. a frame including a first portion , a second portion facing the first portion across an opening in a first direction (D1), a third portion , and a fourth portion facing the third portion across the opening in a second direction (D2) different from the first direction (D1), and including a first surface and a second surface that is located opposite to the first surface ; a supporter including a plurality of supporting members that are arranged in the second direction, the supporting member including a first end that is fixed to the first portion on the first surface side and a second end that is fixed to the second portion on the first surface side; and a deposition mask including a third end that is fixed to the third portion on the first surface side and a fourth end that is fixed to the fourth portion on the first surface side, and including a plurality of holes that are located between the third end and the fourth end , wherein the plurality of supporting members include at least a first supporting member that is closest to an intermediate position between the third portion and the fourth portion of the frame and a second supporting member that is located closer to the third portion of the frame than the first supporting member , and when the first surface of the frame is located above the second surface , the first supporting member in a state of warping downward from the frame with a first warping amount (a1) supports the deposition mask from below, and the second supporting member in a state of warping downward from the frame with a second warping amount (a2) that is smaller than the first warping amount (a1) supports the deposition mask from below. <EOS>