To provide a bracing structure for a frame makes the structure lightweight while being accommodative to employing pipes such as steel pipes as bracing.

A base bracket 8 formed in a cross shape is attached by welding to required positions on a column 5 and a girder 6. Then, connecting brackets 9, each formed in a cross shape, are united by welding with both ends of a brace 7 formed of a pipe such as square steel pipe, and the connecting bracket 9 is connected to the base bracket 8 through connecting plates 10 extending over the base bracket 8 and the connecting bracket 9 and by fastening with fastening members 11.