Cutting tool

A cutting tool comprising:

• a main body which includes a fixing seat fixing a cutting insert or a cutting edge;
• and
• a positioning pin, which includes a cylindrical portion that is used for positioning the main body by being abutted to an abutting surface of a tool rest while the main body is installed in the tool rest, and which is detachable from the main body, wherein
• the main body includes a female screw hole that is provided with a female screw portion and a tapered surface that is symmetric with respect to a center axis of the female screw portion and widens toward an opening thereof,
• the positioning pin includes:
• a male screw portion that engages with the female screw portion,
• a connecting portion that connects an end of the cylindrical portion and an end of the male screw portion, the connecting portion includes a convex surface, and
• a contact portion positioned on the convex surface at a location between the male screw portion and the end of the cylindrical portion,
• while the male screw portion is engaged with the female screw portion and the positioning pin is installed in the main body, the contact portion contacts the tapered surface, and a center axis of the cylindrical portion and a center axis of the tapered surface match with each other, and
• a depth of a screw groove of the female screw portion is set deeper than a height of a screw thread of the male screw portion, so that when the contact portion contacts the tapered surface, the male screw portion and the female screw portion do not contact each other in a radial direction.