PURPOSE: To use a comparatively thin work to produce a grooved pulley efficiently, by using a contracting work machine to form an expanded part of the work formed preliminarily to a shape like a bowl, which has the side expanded in the outside circumferential direction in the center, after compressing and deforming this expanded part.

CONSTITUTION: A work A formed to a shape like a bowl consisting of a side 1 having a required length which has an expanded part 11 in the center, a center flat part 2, and a slope part 3 by the press working is held between a head part 4 and a tail stock part 5 of a contracting work machine B, and a roughing edge tool (omitted in figure) attached to an edge tool attaching table 6 is pressed to the side 1, and both ends are bent while leaving the expanded part 11 as it is to form required pulley side parts 12 and 13. A bottom part finishing edge tool 8 having a plane 81 and slopes 82 and 83 at the tip is pressed to the expanded part 11 to form a pulley bottom part 14 having a required thickness by compression deforming. A groove forming edge tool (omitted in figure) having teeth of a comb is attached to the edge tool attaching table 6, and these teeth are pressed to the bottom part 14, thus rolling grooves (d) to obtain a product D.