To provide a ground heat insulating wall structure for a ground heat utilizing system and its constructing method for storing heat energy with heat radiation and adoption in a ground around a ground heat exchanger, as well as a ground heat utilizing system operation method.

In the ground heat insulating wall structure for the ground heat utilizing system, heat exchange is performed between the ground heat exchanger installed in the ground and a heat pump for cooling or heating operation/cold or hot water operation with heat radiation or adoption from the ground heat exchanger in the state that the ground around the ground heat exchanger is encircled by ground heat insulating walls for efficient heat storage in the ground for a short/long period. In the ground heat utilizing system operation method, the plurality of ground heat insulating wall structures for the ground heat utilizing system are provided for periodic heat storage in the ground heat insulating wall structures.