An electronic device includes a case having a partitional wall dividing the case interior into a first compartment and a second compartment and having one or more interrupting walls in the first compartment. Substrates are disposed in the first compartment and are arrayed in rows, with the interrupting wall being interposed between the adjacent rows. A circuit board is disposed in the second compartment and is electrically connected to the integrated circuits by elements extending through the partitional wall. A signal input terminal and a signal output terminal for the substrates are disposed at one side wall of the case. This structure makes it possible to realize a small-sized device, easy mounting and demounting of the substrates, and unvarying electrical characteristics.