PURPOSE: To assist the displacement of a stand between the folded and unfolded positions by mounting a self-completion type hydraulic balancing means for generating the force counterbalancing the weight of a threading machine.

CONSTITUTION: A wheel 36 of one of support members 16 of a stand 10 and an end cap 34 of a leg 18 of the other support member 14 are engaged with a floor surface S when the stand 10 is both folded and unfolded. In the displacement of the stand 10 between the folded and unfolded positions, the balancing to the weight of a threading machine 12 is provided by a pair of gas spring units 96. These gas spring units 96 respectively comprise a cylinder part 98 pivotally connected to a leg 18 of the support member 14 and a piston rod 100 pivotally connected to a leg 24 of the support member 16.