An insert clamping wedge for clamp-fixing a cutting insert, seated in an insert attachment seat formed in a cutter body, to a recessed portion formed in the insert attachment seat is provided, the insert clamping wedge including: a wedge body, wherein the insert clamping wedge is pressed into the cutter body, wherein the wedge body includes a clamp surface which comes into close contact with the cutting insert and a wedge surface of which a gap between itself and the clamp surface becomes smaller in a press-insertion direction of the wedge body, and wherein the section perpendicular to the press-insertion direction of the wedge body from the wedge surface to the clamp surface being formed in a bell shape.