A dish washing machine comprising: a main body ; a plurality of spray nozzles configured to spray wash water; and a distribution device to distribute the wash water into the plurality of spray nozzles , wherein the distribution device comprises: a cylindrical housing having an inlet formed in one axial end portion thereof and a plurality of outlets that are arranged in a circumferential surface of the cylindrical housing in an axial direction and connected to the plurality of spray nozzles ; an opening/closing member rotatably disposed within the cylindrical housing to open and close the plurality of outlets ; and a motor to rotate the opening/closing member , wherein the opening/closing member 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 , 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 configured to spray wash water; and a distribution device to distribute the wash water into the plurality of spray nozzles , wherein the distribution device comprises: a cylindrical housing having an inlet formed in one axial end portion thereof and a plurality of outlets that are arranged in a circumferential surface of the cylindrical housing in an axial direction and connected to the plurality of spray nozzles ; an opening/closing member rotatably disposed within the cylindrical housing to open and close the plurality of outlets ; and a motor to rotate the opening/closing member , wherein the opening/closing member 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 , 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 that are arranged in a circumferential surface of the cylindrical housing in an axial direction and connected to the plurality of spray nozzles ; an opening/closing member rotatably disposed within the cylindrical housing to open and close the plurality of outlets ; and a motor to rotate the opening/closing member , wherein the opening/closing member 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 , 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 . <EOS>