PURPOSE: To spray cooling water on a cutting part without being restricked in the traveling direction of a device main body by supplying the cooling water only to either one cooling water discharge part so that a cutting torch and a cooling water discharge part where the cooling water is discharged actually are made to this sequential arrangement.

CONSTITUTION: The traveling direction of the device main body 11 is changed over by a clutch 18 and it is selected automatically from which cooling water discharge opening between cooling water discharge parts 24 and 26 the cooling water is discharged. Accordingly, even when the device main body 11 travels in either direction, cooling of the cutting part is made possible. At the same time, since the cooling water supply to the cooling water discharge parts 24 and 26 is carried out automatically by changing over the clutch 18, safety is excellent and efficiency of cutting work is much more improved.