about 780 u00b0 c the contaminated soil which is the subject matter to be purified is not oxidized furthermore since the removed pyrolysis gas is also indirectly heated in a heating chamber 610 having little ventilation most of the pyrolysis gas is removed from the contaminated soil without being oxidized the construction of the contaminated soil purification system according to the present invention is now described in the sequence of the purification processes contaminated soil bs which is the subject matter to be purified is stored in a temporary storage tank b to be ready for the purification processes the contaminated soil bs includes heavy light metals as well as the soil because the heavy light metals are separated from the soil at the pyrolysis apparatus 600 it is preferable that the heavy light metals be separated in advance for the improvement of purification efficiency in addition since the size of soil particles constituting the contaminated soil plays a critical role in the purification efficiency with respect to the combustion temperature of the pyrolysis apparatus 600 it is preferable to sort soil particles by size and to conduct purification processes for the respective sorted contaminated soil bs in order to improve the purification efficiency to this end the temporary storage tank b is transferred to a sorting apparatus 100 through a transfer facility 101 such as a transfer conveyor and then the contaminated soil bs in the temporary storage tank b is put into the sorting apparatus 100 where the particles of contaminated soil are sorted by size or are separated from the heavy light metals referring to fig1 the particles in the contaminated soil bs are sorted.