which enables the control of the descending speed of the rotary rod as well as the rotation speed of the agitating blades when such an apparatus is used in remediation of contaminated soil the rotary rod 6 is lowered into the soil to excavate and stir the soil with continuous monitoring of the pollutant concentration and when it is judged that the tip of the rotary rod has reached the top of the contaminated region a predetermined amount of the microorganism as well as the inducer and air are introduced into the soil by the measuring and control means 13 at this point the descending movement of the rod 6 may be stopped and the still rotating agitating blades mix the introduced microorganism inducer and air herein after referred to as the treating agents with the soil of the contaminated region this ensures a high probability in contact between the pollutants in the contaminated region and consequently increases the soil remediation efficiency thus one treating cycle comprises lowering the rotary rod with monitoring the pollutant concentration to control the descending speed of the rotary rod and the rotation speed of the agitating blades according to the monitoring results and introducing the treating agents into.