Patent ID: 8875555

Claim:
A manufacturing method of a bossed disc-shaped member, being formed a boss portion which projects upright in the thickness direction of a disc-shaped member on a surface of the disc-shaped member, comprising: a level difference formation step which moves a second portion, which is positioned on the inner peripheral side of a first portion in a radial direction of a disc-shaped blank, relative to the first portion in a first direction which is the thickness direction of the blank, thus forming a level difference between the first portion and the second portion; a conical portion formation step which moves the second portion relative to the first portion in a second direction opposite to the first direction, eliminating the level difference, thus forming a conical portion projecting in the second direction in a region on the inner peripheral side of the second portion; and a burring step which performs a burring process on the conical portion, thus forming the boss portion, a pair of dies disposed across the second portion being moved in the first direction in the level difference formation step, and moved in the second direction in the conical portion formation step.