A sealing cap comprising: a cover part coupled to an upper side of a powder container and having a first area, a third area, a second area between the first and the third areas (101, 103) and an opening formed therein, wherein each of the first and the third areas (101, 103) is a horizontal area and the second area is a slope area; and a sealing part having a sealing body, a mounting groove, and a pulling part formed therein, wherein the sealing body is attached to an upper surface of the cover part and covers the opening to seal the opening, wherein the pulling part is formed at one point on an outer edge of the sealing body to extend, and folded by being bent toward an upper surface of the sealing body to thereby overlap the sealing body, wherein the mounting groove recessed toward an inner space of the powder container is formed at a portion of the sealing body overlapping the pulling part, characterized in that said sealing part further comprises a deviation preventing part, wherein said pulling part is in the shape of a ring having a hold hole formed therein, wherein said mounting groove comprises an open upper surface, a side surface, and a bottom surface, a shape of the bottom surface corresponding to a shape of the pulling part; wherein the deviation preventing part is in the shape of an undercut projection which is projected toward a side surface of the mounting groove, and which is formed at a portion around the hold hole, wherein the deviation preventing part is configured such that when the pulling part is mounted on the mounting groove, the deviation preventing part penetrates the hold hole of the pulling part, and hence, a portion of the deviation preventing part being projected upward and a portion of the deviation preventing part being projected toward a side surface of the mounting groove surround the periphery of the hold hole. a cover part coupled to an upper side of a powder container and having a first area, a third area, a second area between the first and the third areas (101, 103) and an opening formed therein, wherein each of the first and the third areas (101, 103) is a horizontal area and the second area is a slope area; and a sealing part having a sealing body, a mounting groove, and a pulling part formed therein, wherein the sealing body is attached to an upper surface of the cover part and covers the opening to seal the opening, wherein the pulling part is formed at one point on an outer edge of the sealing body to extend, and folded by being bent toward an upper surface of the sealing body to thereby overlap the sealing body, wherein the mounting groove recessed toward an inner space of the powder container is formed at a portion of the sealing body overlapping the pulling part, characterized in that said sealing part further comprises a deviation preventing part, wherein said pulling part is in the shape of a ring having a hold hole formed therein, wherein said mounting groove comprises an open upper surface, a side surface, and a bottom surface, a shape of the bottom surface corresponding to a shape of the pulling part; wherein the deviation preventing part is in the shape of an undercut projection which is projected toward a side surface of the mounting groove, and which is formed at a portion around the hold hole, wherein the deviation preventing part is configured such that when the pulling part is mounted on the mounting groove, the deviation preventing part penetrates the hold hole of the pulling part, and hence, a portion of the deviation preventing part being projected upward and a portion of the deviation preventing part being projected toward a side surface of the mounting groove surround the periphery of the hold hole.