To enhance workability when burying an underground buried type tank or the like buried in the underground and for performing heat exchange with a stored fluid or the like, using subterranean heat, and to enhance a heat exchange effect with the subterranean heat after buried.

In this auxiliary burying material, removed earth in drilling or the like, or waste metal is mixed into a coagulant such as cement, when burying the underground buried type tank or the like buried in the underground and for performing the heat exchange with the stored fluid or the like, using the subterranean heat, to be filled into the drilled hole for facilitating the burying, and the auxiliary burying material capable of enhancing effects for heat collection and radiation is provided by serving as a storage layer for the subterranean heat after coagulated after buried.