The authors examined possibility of underground thermal energy use by using ground heat exchanger as short as 6m, from the viewpoint of temperature of ground, in study of underground thermal energy use from shallow underground （Part1）. It was found that the results, higher possibility of practicality of 6m ground heat exchanger in many areas including Hokkaido, in the same way as a conventional ground heat exchanger 100m . In response to this, we carried out a field test by repeating measurement of short time underground thermal quantity and decreasing quantity of heat due to long-term operation. As a result it was confirmed, underground thermal energy use by 6m ground heat exchanger can be available to residential heating and cooling and decreasing quantity of heat after long term operation of 6 months is 51%.
