PURPOSE: To avoid an actuation defect of a gate body to smoothly move it up and down, by preventing foreign materials from piling and getting solid in a female screw of a female screw block or a male screw of a valve spindle and making it possible to apply a lubricant agent in the female screw or the male screw.

CONSTITUTION: A female screw block 3 is fitted to a position which is located at the upper side of the gate body 1 and which is not submerged, so as to be rotatable around the vertical shaft by a bracket 10. The male screw 4a of the valve spindle 4 engaging with the female screw 3a of the female screw block 3 is formed at a position which is not submerged. A hollow shaft 11 which is rotated reversibly by the control of an opening/closing means 7 of the gate body and allows the valve spindle 4 to advance or retract is fixed to the upper part of the female screw block 3. When the sluice gate is fitted in a water supply pipe, a protection pipe 13 is fitted in such a manner that the valve spindle 4 is inserted water-tightly in the lower part of the female screw block 3.