Since it is difficult to avoid the generation of burr in cutting operation, it is necessary to make the burr as small as possible, for saving the time to remove it. Also, the approach angle of the cutting tool influences remarkably the cutting burr, and so it is important to make the approach angle proper. In this study, the effects of the approach angle on the burr root thickness are investigated experimentally, and as a result, for diminishing the size of burr, the new geometry of the cutting tool edge is proposed. The following results are obtained: (1) When the approach angle is 80 degrees or more, the burr root thickness decreases remarkably with the approach angle increasing. (2) The finishing edge with the large approach angle decreases the burr root thickness remarkably (3) The angle and length of finishing edges made as small as possible are more useful for controlling the generation of burr.