To provide a house ventilation system effectively utilizing geothermal source with a simple structure.

This house ventilation system utilizing geothermal heat is composed of a heat exchanging pipe mounted in a vertical cave such as a vertical cave formed in the ground by boring, a vertical cave formed by burying a pipe having a screw-shaped fin at its tip end and buried while being rotated, and a vertical cave formed by utilizing a hollow foundation pile driven in the ground, an air intake means for allowing the air in the heat exchange pipe to be blown out from a blowout port of a first floor and/or a second floor, and an exhausting means for exhausting the air circulated in each living room. The air intake means is provided with an air supply pipe connected with the blowout port of second floor and/or an air supply pipe connected with the blowout port of first floor, and the exhausting means is connected with an air exhaust pipe connected with a suction port formed on a suitable place of the second floor and/or an air exhaust pipe opened at an underfloor spatial part.