To clean soil polluted with PCB (polychlorobiphenyls) by using water and to efficiently separate clean soil particles from soil particles containing much PCB at a low cost.

The soil polluted with PCB is added with water and is introduced into an ejector 5 as a slurry. In the ejector, the slurry containing the polluted soil is taken into jet stream water jetting at high speed. A jet stream is made to collide with the soil particles with PCB stuck and further the PCB is stripped therefrom by turbulence around the soil particles. Air is jetted towards a downstream side by a second air supplying device 56 to add driving force and supply air bubbles to the slurry to which driving force is given by an ejector. Thereby stripped PCB is prevented from re-sticking to the soil particles again. The jet stream is introduced into a cyclone 6, and stripped PCB and fine soil particles with PCB stuck are separated by being contained in an overflow. An underflow is introduced into a floatation separation tank 7 and PCB having hydrophobicity is stuck to air bubbles and is separated by floatation.

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