To provide an ocean-greening and seaweed-cultivating system utilizing deep ocean water, capable of cultivating fish and shellfish and capable of stably supplying a large amount of marine products with high quality and added values.

This ocean-greening and seaweed-cultivating system comprises installing a main float, arranging wave-activated power generation, wind-activated power generation, and wave-breaking units on the main float, laying pipes for sucking the deep water on the main float, and installing a vacuum pump and a place for cultivating the seaweeds, so that an integrated ocean structure is constructed.