PURPOSE: To decrease a drilling time and improve work efficiency, by forming a drill edge and a reamer edge in peculiar construction and increasing a feed speed per one revolution, in the case of a drill reamer of spiral groove type.

CONSTITUTION: A cutting part 1 provides each of two reaming helix grooves 4, 5, forming a reamer edge 6 and a drill edge 7 to be unequally divided and alternately arranged. A chamfer angle of about 118° is formed in a point end lip part 8 of the edge 7 silimarly to the lip part of an ordinary drill, while a chamfer angle of 60° or less with respect to the axial line is formed in a point end lip part 9 of the edge 6. A diameter of the edge 7 is finished smaller by the spread margin of a reamer than the diameter of the edge 6. Further a diamond of excellent wearing resistance or a hard sintered member 12 of cubic crystal boron nitride or the like is also secured respectively to the point end of the edge 7 and 6. By this constitution, a drilling time can be reduced and work efficiency can be improved.