A semiconductor element such as an encapsulated or non-encapsulated semiconductor chip having a multitude of terminals is mounted on one surface of a quadrate substrate. A multitude of connector pins extend from the other surface of the substrate. A plurality of connector lands are formed on a surface of the substrate and electrically connected to the corresponding terminals of the semiconductor element. The connector lands are electrically connected to the connector pins through wiring. The connector pins have a pitch that is larger near the connector lands than at locations farther away from the lands. The pitch between adjacent connector pins is made larger as necessary or desired so as to allow the passage of an increased number of connecting wires between the adjacent connector pins, thus ensuring high density wiring with improved efficiency.