PURPOSE: To make an assembling process into automation by providing a device to pile up a hub and a sleeve respectively indexed, under the condition in which an inserted key is pressed from the outer circumferential direction so as to compress a compression spring.

CONSTITUTION: A hub is positioned on a decided position with a decided phase by means of devices 50, 60 to cut down and index the hub, and the positions of the inserting hole of a compression spring and a key way is decided. Next, the compression spring is inserted into the compression spring inserting hole by means of a compression spring inserting device 90. Hereafter, a key is inserted in the key way by means of a key inserting device 160 under the condition of inserting the compression spring. Meanwhile, a sleeve is positioned on a decided position with a decided phase by means of devices 230, 240 to cut down and index the sleeve, and by means of a piling-up device 200 for the hub and the sleeve, both are piled up each other in the condition of conforming both phases to each other.