To provide a method for manufacturing a twisted angular ring which is used for a joint body capable of simultaneously achieving the fall-proof function and the locking function when it is arranged between a thin-walled connection tube and a joint body, and calked.

A rectangular cut piece 70 as a blank of a twisted angular ring is manufactured out of a metal plate SPL placed on a cutting device CD. An upper face at a left end of the plate is clamped by a clamp member 52. An upper face at a right end of the plate is held by a holder 54. A plate right end (indicated by a broken line) to be delivered by the width t same as the thickness t from a base end 50b is cut by pressing down a cutting unit 60 having a blade part 60a for shearing in the direction of an arrow (α). The rectangular cut piece is sheared by the blade part 60a, different from the existing extrusion-forming, constituting a blank of the twisted angular ring having a sharp ridge for biting.