To provide a fixture supporting tool which has high versatility and a novel structure, applicable to a wire harness and a grommet of any diameter with a unit component.

A fixture supporting tool 10 is extrapolated to a wire harness 22 and disposed between the wire harness 22 and a small opening 24 of a grommet 20 extrapolated to the wire harness 22 in order to fix the grommet 20 to the wire harness 22. A plurality of cylindrical parts 12 having diameter dimensions different from each other are made adjacent in an axial direction, aligned and arranged so as to successively enlarge the diameters from one end portion 16 to another end portion 18 in the axial direction. On the other hand, the plurality of cylindrical parts 12 are integrally connected via a plurality of annular connection parts 14 disposed between the neighboring cylindrical parts 12, respectively, such that the fixture supporting tool 10 is configured in a tubular shape freely elongated/contracted axially and perpendicularly.