A dish washing machine comprising: a main body; a plurality of spray nozzles (311, 313, 330, 340) configured to spray wash water; and a distribution device to distribute the wash water into the plurality of spray nozzles (311, 313, 330, 340), wherein the distribution device comprises: a cylindrical housing having an inlet formed in one axial end portion thereof and a plurality of outlets (212a, 212b, 212c) that are arranged in a circumferential surface of the cylindrical housing in an axial direction and connected to the plurality of spray nozzles (311, 313, 330, 340); an opening/closing member rotatably disposed within the cylindrical housing to open and close the plurality of outlets (212a, 212b, 212c); and a motor to rotate the opening/closing member, wherein the opening/closing member (220, 720) includes a rotation body having a cylindrical shape, and a plurality of sealing members combined with the rotation body to close the plurality of outlets (212a, 212b, 212c), characterized in that the sealing member is combined with the rotation body to be moveable in a radial direction of the rotation body, and wherein the rotation body includes a spacing protrusion that protrudes in a radial direction to maintain the distance between the outer circumferential surface of the rotation body and the inner circumferential surface of the housing. a main body; a plurality of spray nozzles (311, 313, 330, 340) configured to spray wash water; and a distribution device to distribute the wash water into the plurality of spray nozzles (311, 313, 330, 340), wherein the distribution device comprises: a cylindrical housing having an inlet formed in one axial end portion thereof and a plurality of outlets (212a, 212b, 212c) that are arranged in a circumferential surface of the cylindrical housing in an axial direction and connected to the plurality of spray nozzles (311, 313, 330, 340); an opening/closing member rotatably disposed within the cylindrical housing to open and close the plurality of outlets (212a, 212b, 212c); and a motor to rotate the opening/closing member, wherein the opening/closing member (220, 720) includes a rotation body having a cylindrical shape, and a plurality of sealing members combined with the rotation body to close the plurality of outlets (212a, 212b, 212c), characterized in that the sealing member is combined with the rotation body to be moveable in a radial direction of the rotation body, and wherein the rotation body includes a spacing protrusion that protrudes in a radial direction to maintain the distance between the outer circumferential surface of the rotation body and the inner circumferential surface of the housing. a cylindrical housing having an inlet formed in one axial end portion thereof and a plurality of outlets (212a, 212b, 212c) that are arranged in a circumferential surface of the cylindrical housing in an axial direction and connected to the plurality of spray nozzles (311, 313, 330, 340); an opening/closing member rotatably disposed within the cylindrical housing to open and close the plurality of outlets (212a, 212b, 212c); and a motor to rotate the opening/closing member, wherein the opening/closing member (220, 720) includes a rotation body having a cylindrical shape, and a plurality of sealing members combined with the rotation body to close the plurality of outlets (212a, 212b, 212c), characterized in that the sealing member is combined with the rotation body to be moveable in a radial direction of the rotation body, and wherein the rotation body includes a spacing protrusion that protrudes in a radial direction to maintain the distance between the outer circumferential surface of the rotation body and the inner circumferential surface of the housing.