To provide a mounting structure of a coupling member capable of easily connecting an engine side coupling part to a carburetter side coupling part through a coupling member without overlapping clamp bands with each other.

The coupling member 10 for connecting the connection part 12 of an engine 11 to the connection part 14 of a carburetter 13 comprises a joint member 20 allowing the connection part 12 and the connection part 14 to be inserted therein in opposed state and the clamp bands 30 and 40 fastening an engine 11 portion and a carburetter 13 portion on the outer peripheral surface of the joint member 20. Projections 37 and 47 are provided on the outer peripheral surfaces of the opposed portions of the clamp bands 30 and 40. Also the projections 37 and 47 are provided on the upper portions of the clamp bands 30 and 40.