A machine for setting permanent mine-roadway supports is formed by forward and rearward machine parts interconnected by two double-acting advancing rams, and comprises a canopy adapted to carry a horizontal roof bar (or bars) of a permanent mine roadway support to be set in position by the machine, hydraulic displacement means for advancing the canopy towards the roof of the roadway or for retracting the canopy from the roof of the roadway, and preferably two hydraulic rams carried by, or supported from, the canopy and adapted, in use, to act directly below the roof bar to be set and on the upper ends of the two vertical legs which complete the permanent mine roadway support by displacing the upper ends of these legs from an inclined position to a set position in which both legs engage the roof bar advanced by the canopy to the roof.