PURPOSE: To prevent leads from being short-circuited mutually and to prevent bonding wires from being short-circuited by a method wherein, when a plurality of lead frames are laminated, one part of an inner lead is fixed via an insulating layer and an outer lead is arranged in such a way that it is situated on an identical face from an end part of at least a package.

CONSTITUTION: A first lead frame and a second lead frame 1a, 1b are laminated via a polyimide film 10; inner leads 4a, 4b of the frame 1a are extended alternately from different planes and are arranged three-dimensionally. Outer leads 12a, 12b which are situated in a direction opposite to them are extended alternately from an identical plane. A square pad 2 used to mount a semiconductor element and a support bar 13, used to support the pad 2, which is stretched in a diagonal direction from a corner part are formed on the first frame 1a; tie bars 11a, 11b used to maintain an interval of the individual leads are formed at the frames 1a and 1b. Thereby, the frames 1a, 1b are insulated by the film 10; the leads 12a, 12b are made at a uniform height at their tip parts.