PURPOSE: To dispose pins on an entire lower surface of a package in which an integrated circuit chip is mounted downward on a front surface.

CONSTITUTION: An integrated circuit chip 6 is mounted downward on a front surface in a ceramic package 1, and electrically connected to the package 1. A signal wire from the chip 6 is wired to a connecting pad 1a of a lower surface of the package l through a wiring pattern in the package 1. A connecting pad 1a on the lower surface of the package 1 is connected to a connecting pad 2a of the same array of the upper surface of a sealing plate 2 by soldering. The pads 2a on the upper surface of the plate 2 are so electrically connected to pins 3 of the lower surface as to correspond through a wiring pattern 2b in the plate 2. After the pad 1a is connected to the pad 2a, the package 1 and the plate 2 are hermetically sealed with sealing material 4.