To provide a natural heat hybrid soil thermal storage system and a construction method.

This natural heat hybrid soil thermal storage system is composed of a soil thermal storage part 1 constituted of thermal insulating materials 11, 12 each having heat transfer coefficient of 0.05 W/(mK) or smaller and a thickness of 20-500 mm and soil having a side face and a top face surrounded by the thermal insulating materials, a geothermal sampling part 2 constituted of the soil positioned below the soil thermal storage part, a heat exchange pipe 3 passing through the soil thermal storage part and the geothermal sampling part and circulating the outside of the soil thermal storage part and the outside of the geothermal sampling part to circulate water or a non-freezing liquid, a pump unit 5 for circulating water or a non-freezing liquid in the heat exchange pipe, and a control part 6 connected with the pump unit to control the operation of the pump unit. Upper ends of the thermal insulating materials 11, 12 are at positions each having a depth of 200-1,000 mm from a ground surface, and lower ends of the thermal insulating materials are at positions each having depth of 500-3,000 mm from the ground surface. The lower end of the heat exchange pipe 3 is at a position having a depth of 4,000-12,000 mm from the ground surface in the geothermal sampling part 2.