PURPOSE: To easily collect contaminants by providing a vacuum extracting means in a contaminated zone and, at the same time, an electrical inducing means for imparting heat energy to volatile contaminants in the zone.

CONSTITUTION: A well 1 is dug into contaminated soil in a vadose zone and, at the same time, through holes 4 are made through the frame 6 of the well 1. Then, an electrode 5 is provided in the well 1 and electrodes 7 are provided on the ground surface 2 of or in the ground. In addition, the electrodes 5 and 7 are connected to a power source 8. When a direct current or an alternating current is made to flow between the electrodes 5 and 7, heat is generated in the well 1 and the volatilization of volatile and semi-volatile contaminated compound materials in the soil is accelerated and collected to the ground surface through the well 1 by means of a vacuum generating source 3.