PURPOSE: To perform a reamer working efficiently, exactly, precisely and beautifully by a method wherein an indentation is formed in a twisted edge and a high hard piece is inserted into this indentation and it is fixed by brazing, etc. so that the piece may not be removed.

CONSTITUTION: An edge part 1 of a boring reamer having an end mill edge is formed with a plural lines and an end mill edges 3 formed with a straight edge grooves are installed at the edge point of the end mill edtes 3 and together with these, a super left twisting right edge twisting angle is formed and a twisting edge 4 having a slightly large diameter than that of the edge 3 is installed. The edge part 1 consisting of the edge 3 and the edge 4 is formed into one body by means of a cemented carbide and it is fixed at the front end of the shaft part 2 formed with a steel material so that it may not be removed. Next, high hard pieces 5, 6 are formed with a high hard material sintered in a super high pressure which has a hardness harder than the cemented carbide constituting the edge part 1 and these pieces 5, 6 are buried and fixed in a part at the point of the edge 3. With this constitution, a reamer working can be performed exactly, precisely, beautifully and efficiently.