The present invention provides a cutting tool that can firmly hold four types of cutting inserts by one tool main unit. A cutting insert of a cutting tool 1 has an approximately triangular stereoscopic shape including three corner portions. A tool main unit has a fixing portion that can selectively fix a plurality of types of cutting inserts, including: a negative type cutting insert of which angle of the corner portion exceeds 60°, a positive type cutting insert of which angle of the corner portion exceeds 60°; a negative type cutting insert of which angle of the corner portion is less than 60°; and a positive type cutting insert of which angle of the corner portion is less than 60°. The fixing portion has a bottom face that contacts with a bottom face of the cutting insert, and a side wall face that contacts with a side face of the cutting insert. A portion, which contacts with the cutting insert, of the side wall face of the fixing portion differs depending on the type of the cutting insert.

The present invention provides a cutting tool that can firmly hold four types of cutting inserts by one tool main unit. A cutting insert of a cutting tool 1 has an approximately triangular stereoscopic shape including three corner portions. A tool main unit has a fixing portion that can selectively fix a plurality of types of cutting inserts, including: a negative type cutting insert of which angle of the corner portion exceeds 60°, a positive type cutting insert of which angle of the corner portion exceeds 60°; a negative type cutting insert of which angle of the corner portion is less than 60°; and a positive type cutting insert of which angle of the corner portion is less than 60°. The fixing portion has a bottom face that contacts with a bottom face of the cutting insert, and a side wall face that contacts with a side face of the cutting insert. A portion, which contacts with the cutting insert, of the side wall face of the fixing portion differs depending on the type of the cutting insert.