An object of the present invention is to provide a cutting tool that requires the smaller number of parts and can be manufactured at a lower cost. A cutting tool includes: a tool body extending along a central axis and rotatable around the central axis; a cutting insert to be mounted on an insert mounting seat of the tool body; and at least one flow passage provided inside the tool body, the at least one flow passage extending from a back end side toward a front end side of the tool body so as to supply a coolant toward at least a part of the inside of the tool body, a back end side of the at least one flow passage being open at a portion sealed by the tool body and the holding member when the holding member is coupled.