To cut and process metals, or the like also, in addition to paper and improve wear resistance and versatility by forming a cutting instrument of a hard metal by sintering forming, and providing grooves, each having a V-shaped cross section, for folding and tearing off.

A cutting instrument 10 is formed of a hard metal by sintering forming. In the cutting instrument 10, cutters 11 are in a state of being connected by grooves 5 for folding and rearing off them and are formed of a point 14 and a blade 12 having a cutting edge 13. A guide hole 16 to attach the cutting instrument 10 to a holder is provided. The folding and tearing off grooves 15 cross diagonally the long side of the cutting instrument 10, are parallel with each other, and are given a V-shaped cross section perpendicular to the long side, thereby enabling a worn cutter 11 to be folded and torn off and providing a new point 14. The depth of the folding and tearing off grooves 15 falls short slightly of a half of the thickness of the cutter 11. Thus structure makes the blade 12 usable even for the processing of metals, or the like without damage by using a hard metal excelling in hardness and stiffness but lacking in viscosity and elasticity.