PURPOSE: To prevent the generation of force bending an external lead when burr is pushed and crushed, and to obviate the curving of the external lead by placing the external lead in the direction opposite to the surface of a pushing press in a cutting bending process and bending burr generated on the processing of the external lead in a semiconductor device.

CONSTITUTION: A lead frame is placed on a base 5 while upward directing the rear of a package 1. When a tie bar cutting edge 6 is pushed down and a tie bar section 3 is cut, burr 7 can be formed on the surface side of the package 1. A cutting bending process is started under the state. The surface of the package 1 is directed upward in the direction of the package 1 placed at that time. When a lead bending punch 11 is lowered and an external lead is pressed under the state and the external lead 2 is intended to be bent, burr 7 is broken, but force applied to a lead bending mold 9 for the external lead 2 is applied over the whole region of the base at that time, and force intending to curve the external lead 2 in the horizontal direction is not generated. Accordingly, the external lead 2 is not bent in the direction rectangular to the direction of force of a press.