To provide a gear forming die which, in extrusion working of a gear, enables the occurrence of unfilled part in gear formation to be suppressed without increasing a sectional area reduction ratio and consequently enables a gear having good formability to be formed even using a quenching material.

The gear forming die is provided with a columnar mandrel 110 and a cylindrical container 120. On an outer circumferential surface of the mandrel 110, a forming-tooth 113 for forming the tooth in the targeted gear is formed flush with a guiding surface 112. On an inner circumferential surface of the container 120, a pressing part 123 for pressing a blank WK to be formed to the forming-tooth 113, is formed. The pressing part 123 is provided with a preliminary forming part 123a on the upstream side for guiding the blank WK to be formed and a finishing part 123b below the preliminary forming part 123a. The preliminary forming part 123a is formed so as to project from a guiding surface 122 and the tooth having smaller shape than the targeted tooth is formed on the blank WK to be formed by pressing the blank WK to be formed to the tooth 113.