The utility model discloses a falling -preventing device, aim at realizes that the zero deflection of guide rail is connected, has guaranteed smoothly passing through of breaker, reduces the guide rail installation degree of difficulty, the technical scheme who adopts is: include with electric power tower fixed connection's guide rail, be provided with the ladder feet that is used for the climbingof operator person along the axial on the guide rail, the guide rail includes a plurality of fixed connection's in order the guide rail festival, the guide rail festival is H -shaped structure, and the breaker cover is established in the guide rail top flange of festival, is connected with the safety belt on the breaker, and the breaker can be followed the top flange and slided, all set up alongthe both sides of web symmetry on the lower flange of guide rail festival fluted, all through joint fixed connection between adjacent guide rail internode and guide rail and electric power tower, it establishes outside the recess to connect the card.