To improve the work efficiency and speed of attachment and detachment work for a throw-away tip to and from a tool body and to prevent breakage of a throw-away tip and deformation of a tip seat at the time of a corner change.

This throw-away type cutting tool 1 is adapted to screw the throw-away tip 10 to the tip seat 5 provided on the tool body 2 by a clamp screw 30. The clamp screw 30 is loosened by a predetermined amount without pulling out of a female tapped hole 5d provided in the seated surface 5a of the tip seat 5, thereby removing the throw-away tip from the tip seat 5. Thus, the work efficiency and speed of attachment and detachment work can be improved, and further at the time of a corner change, breakage of the throw-away tip 10 and deformation of the tip seat 5 can be prevented.