PURPOSE: To improve construction efficiency by connecting an upper frame of a ground frame for an opening to a hanger that is hung down from a top framework, and by making a lower frame of the ground frame connected to and supported by an erecting hardware that is erected on a bottom framework.

CONSTITUTION: An upper frame 4 of a ground frame 3 for an opening is hung with a hanger 2 from a beam 1a that is provided as a top framework 1. A lower frame 7 of the ground frame 3 is supported by an erecting hardware 6 erected on a beam 5b that is provided as a bottom framework 5. The upper and the lower parts of a concrete panel 8a, provided as a top external wall 8, are connected respectively to the top frameworks 1 and to the upper frame 4 of the ground frame 3. The lower and the upper parts of a concrete panel 9a, provided as a bottom external wall 9, are connected respectively to the bottom frameworks 5 and to the lower frame 7 of the ground frame 3.