To achieve highly accurate press working to a thick part by previously performing position regulation of the width direction preliminarily before supplying an elongated lead frame to a die and reducing the amount of compensation of centering by suppressing the amount of meandering generated when conveying a material.

This mechanism is a mechanism by which the elongated bar 31 progressively supplied is guided in the die for applying press working, which is arranged on the side of upstream process of the die in the conveying direction of the elongated bar 31 and provided with a lower roller guides 32 for supporting the underside of the elongated bar 31 and an upper roller guides 33 which are arranged above the elongated bar 31. The upper roller guide 33 has a guide part 34 which is brought into press-contact with tapered parts 31c on both sides of a thick part 31a which is formed on the upside of the elongated bar 31 and extended in the longitudinal direction.