The outline of pre-cooling system using frozen sand with liquid nitrogen (LN₂) and the results of the tests adopted in the development of the system are described first in this paper. As a result of tests, the following items are confirmed; (1) There were no changes in the physical properties of frozen sand. (2) The properties of the pre-cooled concrete using frozen sand were rather improved. (3) Higher cooling efficiency was attained compared to other pre-cooling methods using LN₂. And next the study on thermal crack control measures utilizing this system and the results obtained from the actural construction of the bottom slab of an LPG in-ground storage tank are mentioned. Consequently, thermal crack in the slab was well controlled and this system was confirmed to be practical.