Patent ID: 8342066

Claim:
A cutting tool for groove-forming an inner circumferential surface of a hole of a workpiece, comprising: a cutting tool main body extending in the shape of a shaft; a cutting edge portion which is provided on a head portion of the cutting tool main body so as to radially-outwardly protrude with respect to the center axis of the cutting tool main body; and a coolant hole which is provided at the cutting tool main body so as to have a first opening at a position apart from the cutting edge portion on a circumferential surface of the head portion of the cutting tool main body, thereby flushing out a coolant from the opening to an axially orthogonal plane orthogonal to the center axis and also in a protruding direction at which the cutting edge portion protrudes; wherein the cutting edge portion is a groove-forming cutting edge portion for forming an annular groove on an inner circumferential surface of a hole formed on a workpiece being rotated around a rotating axis, the cutting edge portion having a rectangular-rod shaped cutting insert attached to the head portion of the cutting tool main body in a radial direction perpendicular to the center axis of the cutting tool main body, and cutting edges formed on the both ends of the cutting insert so as to be parallel to the center axis, and the first opening of the coolant hole faces a direction different from the protruding direction of the cutting edge portion in a radial direction with respect to the center axis, and through which the coolant is supplied to the annular groove.