PURPOSE: To prevent the fatigue failure of a mooring equipment, and to facilitate the repair, examination, exchange or the like of a non-return valve by automatically sinking a floating body in a heavy weather or typhoon to avoid the effect of rough seas, and by supporting the floating body so as to follow the water level to be displaced by the ebb and flow of the tide, and so as to always keep the tension on the wire rope to be in the same condition.

CONSTITUTION: A wire rope adjuster 4 is formed of a cylindrical body in the middle of a wire rope to connect and support a floating body 1 to the sea bottom, one end is open and the other end is closed, and a piston 6 to demarcate the inside into an open chamber side 4c and a closed chamber side 4d is movably fitted inside. The wire rope 5 connected to the sea bottom side is inserted into the closed chamber side 4d from the other closed end of the wire rope adjuster 4 to be connected to the piston, a pressure adjustment assisting device 9 to be communicated with the closed chamber side 4d is provided underwater in an attachable/detachable manner, a non-return valve 10 to communicate the closed chamber side 4d with water is provided, and a weight 7 is fitted to the other end of the wire rope 5 inserted from the open chamber side 4c and connected to the piston 6.