this invention discloses an integrated circuit device including an integrated circuit chip having logic circuits formed therein and a wiring substrate for mounting thereon the integrated circuit chip . the wiring substrate has signal wirings for connecting mutually input terminals and output terminals of the integrated circuit chip . the integrated circuit device includes signal wirings for effecting connections of the input terminals and output terminals of the same integrated circuit chip inside the wiring substrate . the logic circuits inside the same integrated circuit chip are mutually connected by signal wirings formed inside the integrated circuit chip when a wiring length is small , and are mutually connected by signal wirings formed inside the wiring substrate when the wiring length is great .