PURPOSE: To facilitate separation of a one-point mooring device from a barge, by a method wherein a mooring tower, having its lower end rockably supported to a sea bottom and an upper end emerged from a sea surface, and a barge is interconnected through an off-shore yoke and a submerged yoke.

CONSTITUTION: A one-point mooring device comprises a tower base 2, secured to a sea bottom, a tower type mooring device body 1 with buoyancy, which has its lower end coupled to a tower base 2 through a universal joint 3 and an upper end emerged from a sea surface, a turn table 5 and a turn table 4 for connecting a storage barge and are located to the top part and the intermediate part, respectively, of the mooring device body. The bow of a storage barge 14 and the turn table 5 are interconnected through a yoke 6 for storage connection, and the sides of a ship hull and the turn table 4 are interconnected through a fixing rope 10 and the yoke 6. This enables facilitation of separation of the storage barge, and application of a weightless load.