To continuously manufacture a poly V-pulley through one-chuking by cutting the outer circumference of a disk stock made of rolled steel plate of the prescribed thickness formed to the prescribed outer diameter by a cutting roll, parting, expanding the outer circumference in the right-to-left direction, drawing the stock by a drawing roll, and pressing a comb-shaped roll against flange parts on the right and left to form a plurality of V-shaped grooves.

A stock W is held by a die 3 fitted to a rotary spindle 2 of a spinning machine and a press die 4 fitted to a tail stock, and pressing a parting roll 5 against the outer side of the stock W to form a V-shaped groove (a) which is expanded in the right-to-left direction in the V-shape, and the V-shaped groove (a) is ironed in the right-to-left direction by a drawing roll so as to follow the die 3 and the press die 4, and expanded in a plane to form an intermediate stock of a flanged part. A flanged part and a V-shaped formed part of the prescribed thickness are formed by replacing the drawing roll by a forming roll. A plurality of V-shaped grooves are formed to obtain the product by replacing the forming roll by a comb-shaped roll.