A deposition mask comprising a metallic plate, wherein the metallic plate includes: an active area having a plurality of through holes and a bridge interposed between the through holes; and an unactive area provided at an outer portion of the active area, and wherein each through hole is formed in a connection part where a first surficial hole formed in a first surface makes contact with a second surficial hole formed in a second surface opposite to the first surface, a width of the first surficial hole is smaller than a width of the second surficial hole, a depth of the first surficial hole is smaller than a depth of the second surficial hole, wherein the unactive area includes a first half-etching part positioned closer to one end in the longitudinal direction of the metallic plate and a second half-etching part positioned closer to the other end opposite to the one end, wherein each of the first and second half-etching parts includes a groove having a predefined depth, wherein the depth of the grooves of the first half-etching part and the second half-etching part is greater than a depth from the first surface to the connecting part of the through hole, and smaller than a depth of the second surficial hole, wherein the first half-etching part and the second half-etching part are formed on the first surface of the metallic plate, wherein the first half-etching part and the second half-etching part are only formed on the unactive area, wherein the first half-etching part and the second half-etching part include a linear part extending in the vertical direction of the metallic plate and a curved part formed by linking both end portions of the linear part, wherein, a first boundary area being the active area adjacent to the first half-etching part and a second boundary area being the active area adjacent to the second half-etching, the first half-etching part is provided at the unactive area adjacent to the first boundary area and the second half-etching part is provided at the unactive area adjacent to the second boundary area, wherein the curved parts of the first half-etching part and the second half-etching part have the shapes of protruding in the relevant horizontal stretching direction, and wherein a k value calculated in Equation 1 is in a range of 0.65 or more to less than 1, k = H 2 T − H 1, in which the T denotes a thickness of the deposition mask measured in the unactive area, the H1 denotes a thickness defined in a direction of the first surface from the connection part at a point in which a bridge interposed between two adjacent through holes among the through holes has a maximum thickness, and the H2 denotes a thickness defined in a direction of the second surface from the connection part at the point in which the bridge interposed between the two adjacent through holes has the maximum thickness. wherein the metallic plate includes: an active area having a plurality of through holes and a bridge interposed between the through holes; and an unactive area provided at an outer portion of the active area, and wherein each through hole is formed in a connection part where a first surficial hole formed in a first surface makes contact with a second surficial hole formed in a second surface opposite to the first surface, a width of the first surficial hole is smaller than a width of the second surficial hole, a depth of the first surficial hole is smaller than a depth of the second surficial hole, wherein the unactive area includes a first half-etching part positioned closer to one end in the longitudinal direction of the metallic plate and a second half-etching part positioned closer to the other end opposite to the one end, wherein each of the first and second half-etching parts includes a groove having a predefined depth, wherein the depth of the grooves of the first half-etching part and the second half-etching part is greater than a depth from the first surface to the connecting part of the through hole, and smaller than a depth of the second surficial hole, wherein the first half-etching part and the second half-etching part are formed on the first surface of the metallic plate, wherein the first half-etching part and the second half-etching part are only formed on the unactive area, wherein the first half-etching part and the second half-etching part include a linear part extending in the vertical direction of the metallic plate and a curved part formed by linking both end portions of the linear part, wherein, a first boundary area being the active area adjacent to the first half-etching part and a second boundary area being the active area adjacent to the second half-etching, the first half-etching part is provided at the unactive area adjacent to the first boundary area and the second half-etching part is provided at the unactive area adjacent to the second boundary area, wherein the curved parts of the first half-etching part and the second half-etching part have the shapes of protruding in the relevant horizontal stretching direction, and wherein a k value calculated in Equation 1 is in a range of 0.65 or more to less than 1, k = H 2 T − H 1, in which the T denotes a thickness of the deposition mask measured in the unactive area, the H1 denotes a thickness defined in a direction of the first surface from the connection part at a point in which a bridge interposed between two adjacent through holes among the through holes has a maximum thickness, and the H2 denotes a thickness defined in a direction of the second surface from the connection part at the point in which the bridge interposed between the two adjacent through holes has the maximum thickness.