Water saving device for cistern of closet

The utility model relates to the water saving device of a closestool water tank, which includes an operation group and an outlet group. The operation group is a control structure for water output, which includes an actuating pivot bracket, a reeving thimble, and a small mount of water rope sleeve cylinder. The actuating pivot bracket is an operator board located at the side with a crossing rod in the center which is a pivotal axis running from outside to inside of the water tank wall. The reeving thimble is an L-type board fixed on the inner surface of the water tank wall. The small mount of water rope sleeve cylinder a hollow cylinder, the upper end is connected to the end of the actuating pivot bracket crossing rod; the large mount of water rope sleeve cylinder is a hollow cylinder, the upper part is connected to the convex lug of the small mount of water rope sleeve cylinder. The outlet group is a two-pass water liquid outlet star-stop apparatus which penetrates into the bottom of the water tank, including a drain pipe, a floating ball, a large water volume opening pipe and an small water volume opening cover. The large opening pipe is covered on the outlet pipe and can adjust the height of the hollow tube, which is covered by an external pipe and an inner pipe.