PURPOSE: To efficiently open a water gate by the forward and backward repeated operation of a lever by a method in which a driven shaft is positively turned when a driving shaft turns positively or reversely by using an one-way directed clutch.

CONSTITUTION: When moving a lever 14, a driving shaft 1 is turned and paired rotary plates 20 are turned inwardly through coupling plates 19 and 19a. Whereupon, an one-way directioned clutch mechanism 3 becomes coupled, the rotation of a rotary plate is transmitted to an intermediate shaft 15, a pinion 12 is positively turned through a reduction gear 16, a rack part 10 is raised, and the water gate is opened. Then, when returning the lever 14 toward opposite direction, the rotary plate 20 is turned outwardly by a link mechanism 4 and the one- way directed clutch mechanism 3 becomes separated to turn the intermediate shaft 15 in the same direction. By this, the pinion 12 also turns positively likewise to raise the rack part 10, whereby opening the water gate. In this case, the descending of the water gate is automatically locked by the link mechanism 4.