A tool head is provided that can easily correct the shape of a tooth surface. Slot holes are formed in a main head body, that tilt either distally or proximately to the central axis of rotation (CAR) of the main head body. Concave tooth surface blades for cutting concave tooth surfaces are installed in the slot holes that tilt distally, and convex tooth surface blades for cutting convex tooth surfaces are formed in the slot holes that tilt proximately. By changing the amount that the concave or convex tooth surface blades protrude, the cutting portions of the concave or convex tooth surface blades are moved in either distal or proximate directions. By changing the distance from the CAR to the cutting portions in this manner, it is possible to correct the shape of the concave or convex tooth surfaces of a bevel gear.