The invention discloses a single-beam cantilever crane. The single-beam cantilever crane comprises a cross beam, wherein a free end of the cross beam is supported by a surrounding fixing frame, a vertical connecting rod is fixed at the center of the cross beam, the lower end of the connecting rod is connected with a cantilever beam capable of rotating freely around the connecting rod, and the cantilever beam is provided with an electric hoist capable of moving freely along the cantilever beam. In the single-beam cantilever crane, round guide rails are combined with the cantilever beam, so that the single-beam cantilever crane can arrive any position in an execution area in a furnace, everywhere is operable, and secondary manual transportation is unnecessary; the single-beam cantilever crane is simple in over-all structure and convenient to assemble and disassemble; and material is reusable, so that waste is avoided, construction cost is reduced, construction efficiency is greatly improved, and sequentially, employment cost is reduced.