PURPOSE: To increase the rake angle to decrease the temperature of cutting points, and thereby easily discharge chips by making the helix angles of cutting edges unequal to each other in a drilling-cutting tool consisting of a cutting part, on which a required number of cutting edges are spirally formed, and a shank part.

CONSTITUTION: A candle type concave type drilling tool D consists of a shank 1 and a cutting part 2 connected to the shank 1. A pair of cutting edges 21, 22 are spirally formed on the cutting part 2. The helix angles of the cutting edges 21, 22 are gradually decreased from the tip of the cutting part 2 toward the shank 1 side. Further, the spiral flutes 3, 4 are formed between the adjacent cutting edges 21, 22 of the cutting part 2. The widths of the spiral flutes 3, 4 are gradually increased from the tip of the cutting part 2 toward the shank 1 side.