A blind valve, comprising: a valve body unit including a front valve body and a rear valve body that are configured to be disposed between pipes (220, 320) at front and rear locations spaced apart from each other at a predetermined interval and are fastened together by using a bolt; a first nozzle part fastened to the front valve body; a second nozzle part inserted into the rear valve body by passing therethrough and having a spiral protrusion formed on an outer circumferential surface thereof, the second nozzle part being configured to be movable frontward and rearward in an axial direction; a blind plate disposed between the first and second nozzle parts (200, 300) and configured to open and close the pipes (220, 320) by horizontal movement thereof, the blind plate having a gasket provided in a surface thereof that is in contact with each of the first and second nozzle parts (200, 300); a gear unit including a ring gear that has a spiral groove formed in an inner circumferential surface thereof and engaged with the spiral protrusion of the second nozzle part and causes the second nozzle part to be moved forward and rearward in cooperation with rotation thereof; and characterized in that a system block is disposed between the front and rear valve bodies (110, 120) and having a through hole that is formed in the axial direction such that the second nozzle part is moved frontward and rearward relative to the blind plate through the through hole, and a slide groove that is formed in a front surface thereof such that the blind plate is guided to be moved horizontally along the slide groove, the system block being coupled to the valve body unit in an attachable and detachable manner. a valve body unit including a front valve body and a rear valve body that are configured to be disposed between pipes (220, 320) at front and rear locations spaced apart from each other at a predetermined interval and are fastened together by using a bolt; a first nozzle part fastened to the front valve body; a second nozzle part inserted into the rear valve body by passing therethrough and having a spiral protrusion formed on an outer circumferential surface thereof, the second nozzle part being configured to be movable frontward and rearward in an axial direction; a blind plate disposed between the first and second nozzle parts (200, 300) and configured to open and close the pipes (220, 320) by horizontal movement thereof, the blind plate having a gasket provided in a surface thereof that is in contact with each of the first and second nozzle parts (200, 300); a gear unit including a ring gear that has a spiral groove formed in an inner circumferential surface thereof and engaged with the spiral protrusion of the second nozzle part and causes the second nozzle part to be moved forward and rearward in cooperation with rotation thereof; and characterized in that a system block is disposed between the front and rear valve bodies (110, 120) and having a through hole that is formed in the axial direction such that the second nozzle part is moved frontward and rearward relative to the blind plate through the through hole, and a slide groove that is formed in a front surface thereof such that the blind plate is guided to be moved horizontally along the slide groove, the system block being coupled to the valve body unit in an attachable and detachable manner.