The utility model discloses a falling preventing device for ropes and round bars. The falling preventing device comprises a body, a rotating arm, two connection plates, a movable block and a pull ring. One end of the body is provided with a V-shaped through groove, and the other end of the body is provided with a bar-shaped slide groove. The rotating arm is connected with the body in a rotating mode at the middle position, and the movable block is arranged between the rotating arm and the body and located on the opening side of the V-shaped through groove. The two connection plates are oppositely arranged at two sides of the body, one ends of the connection plates are connected with one end of the rotating arm in a rotating mode, a spring is arranged at the connection position, and the other ends of the connection plates are connected with the pull ring in a rotating mode through a pin shaft which penetrates through the bar-shaped slide groove on the body. According to the falling preventing device for the ropes and the round bars, a cam type five-connection-rod mechanism is adopted to increase the braking torque. The V-shaped through groove is adopted to be more suitable for fixing of the ropes and the round bars. The rotating type movable block structure is adopted to reduce the size of the rotating arm and the size of the whole structure as well as increase the braking torque. A spring locking structure is adopted to enable the mechanism to be in a locking state all the time.