To prevent the vibration caused by a backlash by fitting a fixture to the adjusting shaft of the pillow section of a hairdressing chair, fitting a hairdressing model to the fixture via a support, and pressing and biting a wedge section into a gap formed by the adjusting shaft and a shaft hole with the fixture.

This adjusting shaft 13 of the pillow section 12 of a hairdressing chair 11 is extracted from the shaft hole 20 of a recess 19, the adjusting shaft 13 is inserted between the contact section 21b of a fixed plate 21 and a fastening plate 22, and wing nuts 24 are screwed to bolts 23 and lightly fastened to fit a fixture 14. The adjusting shaft 13 is inserted into the shaft hole 20, and the wing buts 24 are fastened to fix the fixture 14 to the adjusting shaft 13. A hairdressing model 16 is fitted to the fixture 14 via a support 15, then the adjusting shaft 13 fitted with the fixture 14 is slightly lifted upward together with the pillow section 12, and a wedge section 18 is pressed and bitten by the fixture 14 into the gap formed by the adjusting shaft 13 and the shaft hole 20.