To provide a denitrification device by utilizing soil which enables a discharge by removing nitrogen from water cleaning human waste.

Human wastewater discharged from a simple flush toilet 1 using a small amount of water is sent to multi-chamber toilets performing anaerobic decomposition and the human wastewater to be decomposed is permeated by capillary to surface soil from a porous pipe disposed in the vicinity of the surface of earth in a soil treating vessel 3, nitrogen of the human waste is converted to nitrate nitrogen to convey it to a water collecting vessel 9 and is denitrified and discharged by fluidizing from the lower part to the upper part the layer of sulfur oxidation and denitrification bacteria carried by particle bodies which is mainly calcium filling the vessel.