To allow a dynamic weight to be incorporated in a handle pipe while rigidly supporting a knuckle guard on the handle pipe.

A knuckle guard mounting structure for a saddle-riding type vehicle includes: a handle pipe 16 disposed on the car width direction outside of a bar handle 15; a grip 40 fixed to the outer peripheral surface 18 of the handle pipe 16; and a knuckle guard 50 disposed in front of the grip 40 and rigidly supported on the handle pipe 16 on the side of the grip 40. In the handle pipe 16, a dynamic weight 57 is supported to float via rubber members 48A and 48B. The handle pipe 16 includes an extended pipe part 45 extending from an outer end 40A to the car width direction outside. A holder member 60 is attached to an extended part outer peripheral surface 45A. A knuckle guard side connection part 59 is fastened to the holder member 60 by a knuckle guard fastening bolt 67.