To improve comprehensive efficiency in a ground heat utilizing system.

The ground heat utilizing system is provided with a plurality of the ground heat exchangers 100 buried in the ground, a heat pump 200 for carrying out heat collection and radiation via a heating medium circulated in each ground heat exchanger 100, an air conditioner 300 heating or cooling a room via a load side heating medium heated or cooled by the heat pump 200, a circulating pump 400 for circulating the heating medium in each ground heat exchanger 100, and a control panel 500 carrying out current transformation amount control of the circulating pump 400. The ground heat exchanger 100 is composed of a hollow pipe body 1, and plural sets of U-tubes 2 housed in the hollow pipe body 1.