To implement cooling effect with simple structure of equipment, by drastically reducing drawbacks of circulation of ground water, in a cooling method, cooling equipment or a cooling system utilizing ground heat.

Ground water level 14 in a impervious wall 10 is lowered by ground water level lowering equipment 6a, 6b. Air is sucked by a suction pipe 1 from a sand stratum 12 from which water goes down and sent to a building 3. While inside of the sand stratum 12 is kept to be negative pressure, air on the ground is moved from the ground surface into the sand stratum 12 to be adiabatically expanded. The air in the building 3 is exhausted from an exhaust port 4. By the above described circulation of air, the cooling effect by the ground heat and cooling effect by the expansion of the air are obtained.