PURPOSE: To enable machining and fabrication of an inner lead frame accurately by forming a connector having a curved opening at the ends of the lead wires of the lead frame and removing the connector substantially simultaneously upon formation of the lead frame.

CONSTITUTION: Inner leads 9 and the ends of the lead 9 are retained and machined to form bumps 13 at the ends of the lead wires of inner lead wires 8 having polyimide supporting frame 12, and a connecting cushion 10 is finally removed. Accordingly, even if external force is loaded at the time of holding and stamping for machining, the inner lead wire 9 may neither be bent nor displaced the position due to the provision of the cushion 10 thereat.