An improved food debris filtering apparatus for a dishwasher and a method thereof capable of more effectively discharging food debris by separating the same from washing water and resupplying the filtered washing water so as to wash dishes, so that dish washing efficiency is increased, which includes a filtering apparatus for filtering washing water polluted during a dish washing operation; a washing water circulation unit for supplying the washing water filtered by the filtering apparatus to a spray arm; a washing water discharging unit, such as a discharging pump, for discharging pan of washing water lo containing food debris to the outside of the system; a flowing path opening/closing unit disposed at a washing water discharging path for selectively opening/closing the washing water discharging path in cooperation with the washing water circulation unit or the washing water discharging unit; and a food debris gathering and storing unit disposed between the washing water circulation unit and the washing water discharging path for filtering washing water filtered by the filtering apparatus and for gathering and storing the food debris contained in the washing water.