PURPOSE: To appropriately maintain the plane precision of the stock by preventing the deformation caused by the pull-in of the stock by a burring punch.

CONSTITUTION: In a die-less burring method, the inner peripheral part of a hole punched in a plate-shaped stock 10 is bent through the preliminary bending, and then, a burring flange 16 is bent in the condition where a burring punch 24 is inserted into the bent part from the direction opposite to the bending direction in the preliminary bending, and the stock 10 is supported by a pad 22 on the side opposite to the side where the burring punch 24 is inserted.