A semiconductor device of a multi-pin structure using a lead frame is provided. The semiconductor device comprises a tab having a chip supporting surface, the chip supporting surface whose dimension is smaller than a back surface of a semiconductor chip, a plurality of leads arranged around the tab, the semiconductor chip mounted over the chip supporting surface of the tab, a plurality of suspending leads for supporting the tab, four bar leads arranged outside the tab so as to surround the tab and coupled to the suspending leads, a plurality of wires for coupling between the semiconductor chip and the leads, and a sealing body for sealing the semiconductor chip and the wires with resin, with first slits being formed respectively in first coupling portions of the bar leads for coupling with the suspending leads.