To provide a stable emplaced/fixed state and to facilitate evacuation movement by installing a private power generating device in a floating structure and operating an electromagnet with the power.

When electromagnets as an electromagnet 3 and a polarizing body 2 are used, the electromagnets are operated by power generated by a solar power generating device 4. Since the facing electromagnet 3 is operated with power from the solar power generating device 4, the polarizing body 2 and the electromagnet 3 are adsorbed to each other or are attracted with each other in a separation state, and therefore, a floating structure 1 can be fixed on a sea surface over the polarizing body 2 installed at a position for emplacing/ fixing it. When the sea surface is expected to be rough due to approach of a storm, power supply to the electromagnets are cut when the electromagnets are used as the electromagnet 3 and the polarizing body 2, and the floating structure 1 can be evacuated and moved to a safety place with a self-propulsion device 5.