PROBLEM TO BE SOLVED: To provide an underwater anchored object state-monitoring system in which the state-monitoring of an underwater anchored object can be performed inexpensively.SOLUTION: An underwater anchored object-monitoring system is provided for monitoring a state of an underwater anchored object installed in the water or on a surface of the water. The system includes: signal transmitting means 11 provided in the underwater anchored object 1； receiving means 21 provided in a ship 2, and receiving a signal sent from the transmitting means 11； location information creation means 24 for creating location information of the ship 2； transmission means 22 for transmitting the signal received by the receiving means 21 and the location information to a control center 3； receiving means 31 provided in the control center 3, and receiving the signal and the location information transmitted from the ship 2； and state determination means 32 for determining a state of the underwater anchored object 1 from the signal and the location information. When a determination is made that the underwater anchored object 1 flows out, alarm means displays the fact on the display unit and transmits mail to designated mobile terminals, mobile phones, smartphones, etc.
