An oxygen strand cutting machine for flame-cutting cast cold and hot slugs, steel blocks and slabs in and after continuous steel casting units comprising: a crane tower; and a boom erected perpendicularly to the continuous casting direction, whereon one or two torch carriages with flame cutters are perpendicularly movable with respect to the cast strand, wherein the crane tower is permanently fixed to the cast strand and includes an articulated arm horizontally pivoting in a set angular sector, on which the boom is rotatably and horizontally mounted, wherein the boom is movably connected to a lifting carriage movable along the articulating arm or the boom and the boom is fitted with roller bearings around which the boom is pivotable to be situated perpendicularly to the continuous casting direction during flame cutting via digital programming, and wherein the articulated arm simultaneously houses driving means, a cooling water supply, and power and control cables as a common line.