A plurality of semiconductor memory chips are stacked on a first main surface of a wiring board, and an interposer chip is stacked on the plurality of semiconductor chips, and a semiconductor controller chip is stacked on the interposer chip. The plurality of semiconductor memory chips are independently and electrically connected with inner connecting terminals formed on the wiring board, respectively, and independently controlled by the semiconductor controller chip which is electrically connected with another inner connecting terminals formed on the wiring board via the interposer chip.