To strongly fix a bracket device without providing a support body or the like with engagement holes or threaded holes and facilitate the adjustment of attachment position.

A horizontal support rod 5 is provided with a pair of engagement pieces 8b facing in the same direction as horizontal engagement grooves 8 in parallel therewith in the front. The bracket device 9 is formed of a base piece 11c and a pair of support pieces 11a and 11b extending rearward from both the end portions in a backward U-shaped cross section, and is made up of a metal support 11 in which locking pieces 14 and 15 that can be engaged with the engagement pieces 8b of the support rod 5 are provided in a bent state at the rear ends of both the support pieces 11a and 11b and a metal fixture 12 having a fitting piece 12b engaged with the engagement grooves 8 of the support rod 5. The engagement pieces 14 and 15 of the metal support 8 are engaged with the pair of the locking pieces 8b of the support rod 5, the fitting piece 12b of the metal fixture 12 is fitted into the engagement grooves 8, and the fixing piece 12c of the metal fixture 12 is joined with the front of the base piece 11c of the support metal member 11 by tightening means 13 and 17.