PURPOSE: To easily execute alignment by down setting a lead side of a multilayer lead frame to electrically connect with a metal plane.

CONSTITUTION: A lead frame of the double-layer structure uses a metal plane only as a ground plane 7. The ground pin 10 is formed shorter than a signal pin 9. A polyimide insulation tape 6 is provided between the lead frame and the ground plane 7 as the metal plane in view of preventing short circuit of an inner lead of the signal layer to be short-circuited through contact with the metal plane. Down-set is carried out for the ground pin 10 of lead frame in such a degree as corresponding to thickness of the insulation tape 6 in order to achieve electrical continuity with the lead frame and ground plane 7 through spot welding such as resistance welding, etc. In this case, the side of the ground plane 7 may be connected to anywhere, if metal portion is exposed, ensuring easy alignment.