To provide a flat die for rolling working, with which strain due to elastic return of the flat-die for rolling working in a biting inclined tooth part is prevented and tooth-shape working precision including highly precise accumulated pitch error can be obtained.

The tooth-top line 9 of the biting inclined tooth part 4 of the flat die, is inclined with respect to the moving direction F of the flat die, and the pitch line 13 and the tooth bottom line 17 of working teeth in the biting inclined tooth part 4, are made parallel to the moving direction of the flat die respectively. The tooth top line 10 of a finishing tooth part 7 is formed to be parallel to the moving direction F of the flat die. Then, the pitch line 15 and the tooth bottom line 19 of the front-half part 5 of the working tooth of the finish-tooth part 7 are formed to be parallel to the tooth top line 9 of the biting inclined tooth part 4, and then biting is only performed in the tooth surface direction at the front-half part 5 of the working tooth of finishing tooth part 7 and the biting of the tooth bottom of the workpiece is not performed. The pitch line 16 and the tooth bottom line 11 of the working tooth at the rear-half part 6 of the finish-tooth part 7 are made parallel to the moving direction F of the flat die respectively.