To suppress cost increase and weight increase affecting a tip part of a workbench, and to increase a moving range of the workbench in the vertical direction.

A workbench elevating device 60 comprises a rotating shaft part 62 rotatably mounted to a leveling bracket 17, a first sheave 71 rotatably mounted coaxially with a pivot position vertically swingably pivoted on the tip part of an extensible arm 80 vertically swingably pivoted to the leveling bracket 17, a first rope member 73 having one end being connected to the rotating shaft part 62, and other end part side extending toward the tip part of the extensible arm 80 and being applied around the first sheave 71 with other end extending downward, a movable sheave 75 arranged in a lower position of the first sheave 71 and connected the other end of the first rope member 73, and a second rope member 77 having one end part being connected to a support bracket 31, other end part side being applied around the movable sheave 75, and end part being connected to a moving member 51 mounted on the workbench 41.