PURPOSE: To ensure an easy electrical connection to an external circuit, prevent a terminal from projecting in the thicknesswise direction of a base board, and make the board thin and compact by arranging the I/O terminals of a multichip module in the form of a thin film and in a row on the principal plane of the board at one side thereof, while being kept capable of being coupled to and clamped with a connector socket.

CONSTITUTION: The major constitutional section of a multichip module comprises a ceramic base board 7 having a thin film multi-wiring layer 8 made of Cu and Al patterns, and a polyamide resin insulation layer on a principal plane, a plurality of electronic parts mounted on and packaged to the principal plane of the board 7, a film type of an I/O terminal pattern group 1 clamped in such a way as freely detachable on a connector socket 11 connected to the parts 9 at one side, and laid in parallel to the principal plane of the board 7 at one side thereof. The socket 11 freely detachable from one side of the board 7 is coupled and clamped as mentioned, and electrically connected to the I/O terminal pattern group 10 laid in a row in the coupling zone plane.