The invention discloses a swing arm device for separating driving wheels of a line inspection robot from a conductor, comprising a central frame, driving wheels, a swing arm driving mechanism and a connecting plate; each of two ends of the central frame is provided with one of the driving wheels, and the bottom end of the central frame is provided with the connecting plate; the central frame is of an axisymmetric structure and comprises supporting arms located at two sides, connecting rods for connecting the two supporting arms together and driving shafts arranged at the lower ends of the two supporting arms; the swing arm driving mechanism drives the driving shafts to rotate; guide pins are arranged on positions where the supporting arms are connected with the connecting plate; one end of each guide pin is pinned in each guide plate, and the other end of each guide pin is connected with each execution hook; and the execution hooks are fixedly arranged at two ends of the driving shafts and move along the routes of the guide plates under the drive of the driving shafts to drive the driving wheels at the top end to swing and restore. The swing arm device is simple in structure, convenient to operate and independent and can be easily connected with different line inspection robots.