To provide an apparatus for treating liquid waste by using an effect of an electric charge, one unit of which can corresponds to the conventional apparatus which is used for removing mixed foreign matters (dust, mineral oil and water) so that the service life of a treating liquid such as a machining liquid is prolonged to decrease industrial waste and impurities are decreased to stabilize the quality of the treating liquid and in which dust removal and oil separation are performed separately.

The apparatus for treating liquid waste by using the effect of the electric charge includes: a treatment tank 12 in which the liquid to be treated is put; a plurality of electrode plates arranged in the treatment tank at regular intervals; and a power unit for impressing a voltage between the adjacent ones of the plurality of electrode plates. A dust collecting body 20 comprising many voids surrounded by a fiber having flexibility, elasticity and electrifiability is arranged between the adjacent electrode plates. A discharge port-bored plate having electric non-conductance is arranged above the dust collecting body to be moved freely to the vertical direction so that the amount of the dust to be captured by the dust collecting body can be detected from the outside.