To provide an underground intercalation gadgetry which can perform a cleaning operation to contaminated soil without the necessity to move the gadgetry frequently inside a trial boring pipe penetrating through the ground.

This underground intercalation gadgetry 1 is designed to perform a cleaning operation to the contaminated soil by inserting the gadgetry 1 into a trial boring pipe 23 penetrating through the ground. The underground intercalation gadgetry 1 comprises one sleeve 3, a plurality of expandable pipes 5a, 5b, 5c and 5d which are fitted into the sleeve 3 and a plurality of first inner pipes 7a, 7b and 7c and a second inner pipe which are introduced into the sleeve 3. In addition, compartments 13a, 13b, 13c and 13d are airtightly formed to the outside in each gap between the expandable pipes 5a, 5b, 5c and 5d and the sleeve 3. Further, a first communicating hole 15a which makes the interior of the sleeve 3 communicate with the outside, is pierced through the sleeve 3 each between the expandable pipes 5a, 5b, 5c and 5d. On top of that, a second communicating hole which makes each compartment 13a, 13b, 13c and 13d communicate with the interior of the sleeve 3, is pierced in the region of the sleeve 3 corresponding with each expandable pipe 5a, 5b, 5c and 5d. Besides, the first inner pipes 7a, 7b and 7c are made to communicate with each of the first communicating holes 15a, and each compartment 13a, 13b, 13c and 13d is made to communicate with the second inner pipe through each second communicating hole.