A semiconductor device is comprised of a memory cell array with multiple memory cells arranged in a matrix, multiple bit-line pairs provided for each memory cell column in the memory cell array, multiple input/output circuits provided respectively corresponding to the multiple bit-line pairs, and as interface control circuit that controls the data input/output to the multiple input/output circuits when performing the data write and data read for each memory cell row in a normal mode. The interface control circuit is comprised of a selection circuit. When the data write and data read are performed for each memory cell row in a test mode, the selection circuit selects the data input/output to one of first input/output circuit and a second input/output circuit, respectively corresponding to a first memory cell included in the memory cell row and a second memory cell adjoining the first memory cell, according to a test address.