To provide a method of cleaning contaminated soil by heating at a low temperature.

The contaminated soil containing a volatile organic compound is supplied to a rotary kiln 1 and dried by heating at a low temperature below the boiling point of the volatile organic compound. The fine particles of the contaminated soil is accompanied with a waste gas discharged from the rotary kiln 1 and scattered to the downstream and the scattered fine particles are collected by an inertia dust collector 9 or a bag filter 10. The collected fine particles are supplied to a heating apparatus 19 to vaporize the organic compound stuck to the fine particles.