PURPOSE: To easily operate, simplify tools and devices, and the like used for manufacture, restrain consumption of consumable goods so as to reduce running cost, and prevent generation of chip on the cutting section, in manufacturing a ditch cover.

CONSTITUTION: In a cutting tool 11 for cutting off the end part of a bar 4 used for structural material as a surplus part 4a, it is formed into a nearly pipe-like shape, and the size of the end face opening of the pipe-like tool is formed so that it can be freely inserted to the surplus part 4a and play at inserting is small. When the cutting tool 11 is inserted to the surplus part 4a, the length of the tool is set so that the surplus part 4a can be bent by lever action while setting the end part on the inserting part side of the cutting tool 11 as the fulcrum and the other end as the point of force, and the mechanical strength of the tool is set so as to serve as the lever bending the surplus part 4a.