To provide a fixing structure of a protective fence prop on a covered ground part capable of preventing a protruding end of an anchor bolt from being fractured and preventing occurrence of unnecessary wavering of a protective fence.

The protective fence prop 10 is firmly fixed on the covered ground part G by fastening an anchor nut 42 tightly by preventing a supporting fitting 1 from being deformed when fastening the anchor nut 42 tightly by a horizontal part 12 and a straight erected part 11 of the supporting fitting 1 to prevent occurrence of unnecessary wavering of the protective fence 100. However, since the horizontal part 11 and/or the straight erected part 12 are deformed if the load being almost equal to the load fracturing the protruding end 41 of the anchor bolt is applied to the supporting fitting 1, it is possible to prevent the anchor bolt from being fractured when a vehicle collides against the protective fence 100.