This is a geothermal ventilation system that was originally developed so that anyone can easily use geothermal heat, which is available in summer and winter and anywhere as long as the ground is available. The system has been used in homes, public facilities, factories, agricultural facilities, etc., not only in Japan but also in the U.S. and South Korea, where it has been installed in over 2,000 buildings. The ventilation system also has an air purification function, making it effective in preventing infectious diseases.