The invention discloses a safety device for electrical workers, and particularly discloses a safety rope self-locking device. The safety rope self-locking device comprises a shell in a rectangle shape, the shell is of a hollow structure, a plurality of baffles are arranged in the shell at intervals and divide the inside of the shell into a plurality of rope containing grooves, and each rope containing groove is provided with a rope self-locking device. Each self-locking device comprises a rotating shaft, a torsion spring and a locking plate. The rotating shafts are arranged on the bottoms of the rope containing grooves, the locking plates and the torsion springs are sequentially arranged on the rotating shafts, the locking plates can rotate left and right along the rotating shafts, and one faces, corresponding to safety ropes, of the locking plates are zigzag and used for being meshed with the safety ropes. Thus, a plurality of safety ropes correspondingly pass through the rope containing grooves, and the safety ropes are meshed tightly through the zigzag faces on the locking plates. When the electrical workers make mistakes, self-locking can be achieved, falling can be prevented effectively, and the safety rope self-locking device has the advantages of being simple in structure and high in self-locking speed.