A tool manufactured by brazing a hard sintered body such as a diamond or cBN to a tool substrate through a bonding layer comprising at least one of Ti and Zr by 15-65 wt % and Cu. Two ridges of the tool substrate on both sides each has a first ridge adjacent to and aligned with a ridge of the hard sintered body and a second ridge provided nearer to an inscribed circle of the tool than is the ridge of the hard sintered body. Also, an upright side face and a bottom of each seating groove formed in the tool substrate intersect each other at an angle smaller than the intersecting angle between a back side and a bottom of each hard sintered body.