Method for retaining member by caulking

A method for retaining a member by caulking, comprising:

• bending an end of a workpiece along a corner portion of the member by a caulking surface of a caulking roller;
• applying a pressure to a pressure receiving shoulder portion, which is formed coaxially on the outside of a bent side of the end of the workpiece, in a same direction as a caulking pressure applied to the caulking surface so that a caulking process is performed to form a caulked portion, and the member is held along a base of the workpiece by a clamping force of the caulked portion;
• and
• setting a timing for starting a caulking end process to a timing when a caulking load applied to the caulking roller during the caulking process or a caulking torque for rolling the caulking roller undergoes a specific change indicating that the member begins to be strained.