To complete concrete placing in foundation work at one time by stably holding a cantilever type garage by joining columns of the cantilever type garage by bolts to a shape steel foundation frame having horizontal level adjusters.

A foundation frame A is constituted in a rectangular shape by H shape steel 2 and 2 and C shape steel 3 and 3, and connecting parts 4 and 4 to join columns 1a and 1a of a cantilever type garage by bolts are arranged so that the center of gravity of the cantilever type garage is positioned on the foundation frame A, and a reinforcing welding wire net 6 is unfolded in the frame. First of all, a hole H in which the foundation frame A is embedded is excavated, and cobble stones (g) are laid, and the foundation frame A is arranged on it, and the columns 1a and 1a of the cantilever type garage are joined to the connecting parts 4 and 4 by bolts, and the cantilever type garage is erected, and a horizontal level of the foundation frame A is adjusted by horizontal level adjusters 5 arranged in the four corners of the foundation frame A, and concrete is placed. Therefore, the cantilever type garage is stably held only by the foundation frame A, and concrete placing can be completed at one time.