Exchangeable head cutting tool

An exchangeable head cutting tool comprising:

• a tool main body made of a hard material and having a mounting hole with concave portions in an inner peripheral surface thereof;
• a connecting member made of a metal material having a lower hardness than the hard material and having a cylindrical mounting portion;
• and
• a diameter expanding member having a higher hardness than the connecting member, wherein
• the tool main body and the connecting member are joined by inserting the cylindrical mounting portion into the mounting hole, and by plastically deforming the mounting portion so as to expand a diameter thereof, thereby bringing an outer peripheral surface of the mounting portion into close contact with the inner peripheral surface of the mounting hole and thus making the outer peripheral surface of the mounting portion engage with the concave portions in such a manner that a portion of the outer peripheral surface of the mounting portion penetrates into the concave portions due to plastic deformation,
• the diameter expanding member is press-fitted into and fixed to an inner peripheral portion of the mounting portion, and
• the mounting portion is plastically deformed by the diameter expanding member.