To improve the construction efficiency of a foundation structure in the construction field, to drastically shorten a construction period to reduce construction costs, and to economically and safely construct a housing structure.

There is provided a method for constructing the foundation structure, according to which unit foundation frame bodies 10 are carried in a foundation work area 1 in the construction field of the foundation structure, and they are connected and fixed to each other. Then, a ready mixed-concrete material C is poured into the frame bodies, and it is cured and solidified, to thereby construct the foundation structure. Each unit foundation frame body 10 is formed of a base portion 11 mounted on the foundation work area 1, support members 13 erected on the base portion 11 along the housing structure at locations inside and outside the same, permeable form members 17 formed of a meshed steel plate, which are arranged inside and outside the foundation and fixed to the support members 13 in a manner being opposed to each other, and reinforcing bars 21 rigidly arranged in the frame body 10. The unit foundation frame body 10 is comprised of a bottom connecting means 31 for connecting a bottom thereof to a bottom of the frame body 10 adjacent thereto, and rigidly tying the bottom to the foundation work area 1, and a top tying means 38 for tying a top portion thereof to a top portion of the adjacent frame body 10.