PURPOSE: To enable burying of an electric wiring box correctly by providing a box fixing material wherein elastically deformable engaging materials are oppositely provided on the inner wall of the electric wiring box.

CONSTITUTION: When a fixing material 10 is attached on a mold frame substrate 14 and an electric wiring box 11 is placed thereover, an electric parts attaching portion 13 of the electric wiring box 11 is engaged to an elastic engaging portion 12 of the fixing material 10 through the elastic force thereof and, therefore, positionally fixed on the fixing material 10. Accordingly, when concrete is flowed, buried, and vibrated therein, the electric wiring box 11 is, in a state of being positioned on the fixing material 10, positionally regulated by the elastic engagement of the elastic engaging portion 13, as a result, the displacement thereof is prevented and, thus, it is buried in the predetermined position of a concrete slab.