PURPOSE: To efficiently cut a shape steel material of large size without causing the necessity for replacement of a cutter at each different size of the material, by providing the cutter to the point end of a long neck shaped cylindrical body longitudinally and vertically moved fuether turned around a fixed bed.

CONSTITUTION: A cutter 18 provided to the point end of a long neck shaped cylindrical body 15 is constituted such that its moving can be performed, needless to say, longitudinally and vertically also turning motion can be performed in the horizontal direction (lateral direction) around a fixed bed 1 by turning a holding bed 3. A position of the cutter, in case of cutting, for instance, a large size shape steel, is moved along the surface of a steel material 31, and the cutter smoothly appears also in a recessed part 30 then the large size steel material can be efficiently cut by the cutter of small diameter.