Abstract: A gas cutting machine for cutting a cast strand includes a torch and is movable downward together with a cut portion of the cast strand. In the neighborhood of the torch is located a movable hood which is movable in synchronism with vertical lifting operation of the gas cutting machine, and an expansible sludge discharge pipe and an expansible suction duct communicated with a suction blower are mounted on the movable hood. A divisional dummy bar is utilized and includes an upper and lower divisional dummy bar, and a connector for connecting the divisional dummy bars together. The connector comprises an upper member and a lower member, the upper member having in its inner cavity a pair of levers pivotally supported on lever shafts and the lever havign a locking roller at the lower end thereof. The lower member includes a hooking head held by a pair of locking rollers.