Formed rotary cutting tool

A formed rotary cutting tool that is to be moved relative to a workpiece in a direction perpendicular to an axis of the cutting tool while being rotated about the axis, so as to cut a groove having a predetermined shape, in the workpiece,

• the cutting tool comprising a cutting edge defining a cutting edge diameter that is increased and reduced in a direction of the axis, so as to have at least one neck portion in which the cutting edge diameter is minimized,
• the cutting tool comprising a roughing portion which is provided on a periphery thereof and which is constituted by a succession of protrusions and recesses arranged in the direction of the axis,
• the roughing portion including a fine roughing portion that is provided in at least one of the at least one neck portion, and another portion that is provided in a portion that is other than the at least one of the at least one neck portion, and
• the fine roughing portion of the roughing portion being different in characteristics from the another portion of the roughing portion.