To provide a method for manufacturing a rolling shaft with a deep groove having thin diameter by using rolling dies, with which a screw shaft with the deep groove and the thin diameter can be manufactured.

The method for manufacturing the rolling shaft with thin diameter and deep groove, is performed the followings, that the rolling die 1 for manufacturing double-start thread, in which a right angle cross sectional surface at a tooth tip part shape of a screw tooth 3 of the die 1, is formed as semi-circle shape having the radius R and the interval between the surface 2 of the die and the tooth 3 is made to chamfering with the radius (r), and the surface shape of the cross sectional face in the longitudinal direction, is constituted of a biting part 4 having the biting angle of 1 to the center axis of the die, and a relief part 6 having the relief angle 2 to a parallel straight line part 5 of the parallel portion in the surface shape of the cross sectional face in the longitudinal direction and further, a relief surface 9, respectively chamfered with an inclining angle 3 from the rolling die surface 3 to both end part of the screw tooth 3, is formed; and the length ratio of the biting part, the parallel line part and the relief part are constituted with 2:2:1, and a pair of rolling dies is fitted to a rolling machine and the main shafts are slightly inclined and the blank under beforehand arranging both end parts of the round bar blank 7 having the axial diameter of 4 times of the radius R is inserted between the rolling dies.