The present invention relates to a ballast water treatment system including an air compressor for compressing air; an air receiver tank for receiving the compressed air from the air compressor and storing the compressed air; an oxygen generator for generating oxygen from the air supplied from the air receiver tank; an oxygen receiver tank for storing the oxygen supplied from the oxygen generator; an ozone generator for generating ozone from the oxygen supplied from the oxygen receiver tank; a ballast water pump for pumping ballast water; an inflow line for transferring the ballast water from the ballast water pump; a ballast water tank for receiving the ballast water from the inflow line and storing the ballast water; and an ozone injector for injecting the ozone into the ballast water of the inflow line.