There is disclosed a resin-sealed semiconductor device in which plural circuit portions integrally having inner and outer terminals are arranged two-dimensionally substantially in a plane and electrically independent of one another, and have leads for integrally interconnecting the inner and outer terminals, surfaces of the circuit portions are semiconductor element mounted faces with the inner and outer terminals and the leads forming one plane, the inner terminals and the leads are thinner than the outer terminals, back surfaces of the circuit portions are provided with terminal faces of the inner and outer terminals, a terminal mounted face of the semiconductor element is mounted via an insulating layer onto the semiconductor element mounted faces of the circuit portions, and the semiconductor element terminals are electrically connected with wires to the terminal faces of the inner terminal, and the whole is sealed with a resin in such a manner that the outer terminals are partially exposed to the outside. An occupation ratio of the semiconductor element in the semiconductor device is enhanced, the semiconductor device can be miniaturized, and a mounting density onto a circuit board can be enhanced. By forming outer electrodes on the outer terminals, multiple pins can further be provided, which is difficult with a small-sized semiconductor device such as conventional TSOP and the like.