To measure the strength of the end part of the material processed by a cutter to be bonded by providing a fixing means pressing first and second edge tool elements to the other side wall of recessed grooves to fix them.

The press screws 13 of the fixing means 5 provided to the other side wall of each of second edge tool elements 4 is pushed out to each of the recessed grooves 2 in bed metals 1 same in shape. When the engaging groove 15 of the second edge tool element 4 is pressed, the second edge tool element 4 is pressed to one side wall of the recessed groove 2 to be strongly fixed and the movement in a rotary direction thereof is prevented. The axial movement of a first edge tool element 3 is also prevented by the tight fastening of a fastening member 7. When the second edge tool element 4 is cut in wood, the wood is subjected to cutting processing in a notched state according to the shape of the second edge tool element 4 by the ridge edge parts and trough edge parts continuously adjacent to each other of a second main blade member.