To provide a geothermal heat pump system having high maintenance performance.

This geothermal heat pump system includes a geothermal heat pump device 1 utilizing geothermal heat as a heat source, a plurality of in-ground heat exchange pipes 5 which are buried in the ground and in which a heat medium is circulated, and horizontal pipes 7 which respectively connect the in-ground heat exchange pipes 5 adjacent to each other among the in-ground heat exchange pipes 5 buried in the ground, or the in-ground heat exchange pipe 5 and the geothermal heat pump device 1, and in which the heat medium is circulated. The geothermal heat pump system further includes a U-shaped groove 11 buried in the ground and having a top face opened toward a surface of the ground, and a U-shaped groove cover 12 covering the opening of the U-shaped groove 11. The U-shaped groove 11 and the U-shaped groove cover 12 are disposed in a state that a top face of the U-shaped groove cover 12 is roughly flush with the surface of the ground in a state that the U-shaped groove cover 12 is mounted on the U-shaped groove 11. Connecting sections 9 of the in-ground heat exchange pipes 5 and the horizontal pipes 7, and the horizontal pipes 7 are disposed in an internal space H formed between the U-shaped groove 11 and the U-shaped groove cover 12.