A mold for a use of making a fuel cell separator comprises: a first flow path forming portion to form a cooling medium flowing path, or to form an oxidizing gas flowing path, or to form a fuel gas flowing path; and an injection gate to shoot out a forming material settled on the first flow path, andor disposed at near place with the first flow path. In other words, the improved EPD has dual switching modes. Such mechanism includes a cam surface located along a first extension of a cam arm which pivots around a fixed pivot pin carried by the body of the backup.