To provide a disaster-suffering preventive structure of and a disaster- suffering preventive method of a foundation structure excellent in cost and easily applicable to an existing structure.

A part of the ground G around pile footings 7 is improved, and foundation improving bodies 15 are formed so that the upper end parts 15a and the lower end parts 15b are respectively positioned in an upper nonliquefied layer 5 and a lower nonliquefied layer 3 and the central parts 15c are positioned in a liquefied layer 4. When an earthquake occurs, at least a part of horizontal force acting in the ground G is shared with the foundation improving bodies 15, and horizontal directional relative displacement between the upper/lower nonliquefied layers 5, 3 is regulated by the foundation improving bodies 15.