To provide a winding device for closing operation in a water channel gate capable of significantly reducing the working burden for winding a gate body, and also capable of reducing the working hours.

This winding device is constituted to close a gate body 4 by winding up the wire 8 fitted to the gate body 4. Then, the body 6 of the winding device is housed in the inside of an underground chamber clock 5, and the output shaft 6a of the body 6 is directly connected to the reel 7 of the wire 8, and an operation handle 9 is connected to the input shaft 6b so as to be set respectively in such an attitude as it is projected from the housing position inside the chamber block 5 to the above of the ground surface. When the operation handle 9 is erected, the input shaft 6b can be rotatably driven by fitting a crank handle 12 to the upper end thereof, so that the rotation can be transmitted to the reel 7.