PURPOSE: To provide an inexpensive device with four rolls for working a shaft material which has simple structure and high rigidity by making driven rolls like disks and holding the outer peripheral part with a driving roll pair and supporting members.

CONSTITUTION: Grooves are constituted of the opposed driving roll pair 1, 1 and driven roll pair 2, 2 which is opposed to each other on both sides of this roll pair 1, 1. In that device, the driven roll 2 is made like a disk or doughnut and constituted so that the outer peripheral part is held with the driving roll pair 1, 1 and supporting members (back-up rolls) 7. The groove occupancy angle of the driving roll 1 is formed in the range of 100-140° and the groove operating angle except groove edge relief angle is formed in the range of 90-140°. The groove occupancy angle of the driven roll is formed in the range of 40-80° and the groove operating angle except the groove edge relief angle is formed in the range of 20-80°. In this way, the working method that the dimensional accuracy of the product of shaft material is high, wrikle and scratch aren't generated and work is easy can be provided.