PURPOSE: To produce a high effect not only for heating, but also for cooling, by utilizing a foundation heat storage body as a heat storage body facing a dwelling space of a house or the like directly.

CONSTITUTION: This foundation is constructed by filling cobble stones, crushed stones 4 or the like in a box type structure of reinforced concrete 1, 2 and 3 and it is resistant completely to external moisture and heat except an upper floor part 3 facing a dwelling space and has a moisture-proof material 6 and a heat insulating material 5. By burying cold-hot water circulating pipes 8A and 8B in the crushed stones 4 or the like and by circulating hot water in winter, accordingly, a foundation heat storage body is made to be of high temperature and air having a volume of about 30% of the one of the cobble stones or the crushed stones 4 being filled is also made warm air. By circulating cold water in summer, the foundation heat storage body is made to be of low temperature and the air of about 30% of the volume of the cobble stones, the crushed stones 4 or the like is also made cool air. This function of producing the cool-warm air is utilized. In other words, air tubes 3F and 3G are provided in the upper floor part 3 and the air is circulated through each room of a house by circulating pipes 9C and 9D for sending the cool-warm air, a fan 11 for sending the cool-warm air and a cool-warm air return port 11E, so as to be used for cooling or heating.