PURPOSE: To reduce working time and make work easy by joining the V-groove member made by interposing a foil-like braze plate between the contacting tapered pieces of adjacent V-groove members and laminating these in a vertical direction to a pulley.

CONSTITUTION: A through-hole 1b is provided to the outside circumference 1a of a rotor 1. The bottom part 2c of a V-groove member 2 positioned below is lightly press-fitted to the outside circumference 1a of the rotor 1. The upper V-groove member 4 is likewise lightly press-fitted. A braze plate 6 of copper of a hollow disc shape is grasped and pressed between the tapered pieces 2a and 4b of the V-groove members 2, 4. Additionally, a ringlike braze material 5 composed of copper braze is set to the corner part formed by the tapered piece 4a of the V-groove member 4 and the outside circumference of the rotor 1. These are held by jigs and are heated in this vertical position relation. The foil-like braze plate 6 brazes the contact part of the tapered pieces 2a, 4b and also joins the bottom part 2c and the outside circumference 1a. Also, the ringlike braze material 5 joins the bottom part 4c and the outside circumference 1a. The through-hole 1b puts the space of the pieces 2a, 4b in the same atmosphere as that in a furnace, thereby preventing the hindrance of brazing.