PURPOSE: To carry out uniform heat cutting by forming a proper recessed part on a corresponding guide rail part in the vicinity of the position right under a working head.

CONSTITUTION: A guide rail 21 parallel to the longitudinal direction of a frame 3 is provided. A work table provided with plural work supporting members 15 provided with guide rollers 47 guided by this guide rail is provided freely movably in the longitudinal direction of the frame 3. The working head 13 to carry out heat cutting on works supported by the supporting members 15 is provided above. The working head 13 is made freely movable in the direction to cross orthogonally to the longitudinal direction of the frame 3. The proper recessed part 49 is formed on the corresponding guide rail 21 part in the vicinity of the position right under the working head 13. By this method, heat cutting can be carried out without causing defective cutting.