A ballast water treatment apparatus for a ship includes a water collection part for collecting sea water, a forward osmosis process unit for producing ballast water and treatment water obtained by desalinating the sea water collected through the water collection part, and a ballast water tank for storing the ballast water produced by the forward osmosis process unit. Since the sea water is treated using a forward osmosis process, fresh water required within the ship can be supplied and the treated sea water can be used as ballast water. In addition, since waste heat and carbon dioxide generated in the ship are used to treat the sea water, the ballast water can be treated and produced in a low-cost and high efficient manner.