The invention discloses a device used for fixing electrical elements in an installation box. The device comprises installation plates and nut columns. The installation plates are fixedly disposed in the electrical element installation box. The nut columns comprise column bodies and head parts, which are integrated together. Each of the head parts is connected with one end of the corresponding column body, and the size of the cross section of each of the head parts is greater than the size of the cross section of each of the column bodies, and an installation hole provided with internal screws is disposed from each of the head parts to the corresponding column body. Each installation plate is provided with a plurality of nut columns, and by adopting an arc welding way, the column bodies pass through the installation plates, and are connected with the installation plates in an welded manner. The device is advantageous in that a structure is simple, and production is convenient; the nut columns are fixedly installed, and the installation of the electrical elements is facilitated.