To provide a press forming die of a developer amount regulating blade which is a function member used in an image forming apparatus, more particularly a developer amount regulating blade free of flaws at a side end contacting a roller and a forming method.

The press forming die has a positioning mechanism of a workpiece and consists of an upper die and a lower die. The positioning mechanism includes one piece each of the following so as to oppose each other in a way as to hold the workpiece in-between; a press cam which is moved in a vertical direction by up and down movement of a die plate disposed on a sub-plate of the lower die; a positioning guide of the workpiece which moves in the transverse direction of the workpiece in compliance with the vertical movement of the press cam; and a compression coil spring for releasing the positioning which releases the positioning of the workpiece by being released of the pressing in a downward direction that the press cam receives.