PROBLEM TO BE SOLVED: To provide a metal fitting for a frame foundation and a construction method of a frame beam material using the metal fitting for the frame foundation in which, when installing a solar cell module or the like through the frame beam material to an upper part of a base body provided on the ground, a construction error of a height or inclination of the base body can be adjusted by simple work.SOLUTION: A second bolt inserted through a second hole part on a side supporting plate of a dedicated adjustment metal fitting is inserted through a bolt hole in an upper part of a base body and fastened while adjusting a height and a mounting angle of the dedicated adjustment metal fitting. On the other hand, a flange surface is locked by a first pawl part by hanging a groove part of a dedicated metal fixture on a flange-side end portion of a frame beam material placed on an upper supporting plate of the dedicated adjustment metal fitting, and a first bolt inserted through a guide hole part of the dedi
