semiconductor memory device employs all of the plurality of control pads cpad 2 commonly shared by the memory banks for example in the device of fig2 if data is read written from in the first bank area firstly data is read written from in the first bank area b 11 of the first memory bank ba 21 through the i o pads iopad 11 u2013 iopad 14 and then data is read written from in the second third and fourth bank areas b 21 b 31 and b 41 of the second third and fourth memory banks ba 22 ba 23 and ba 24 through the i o pads iopad 21 u2013 iopad 24 iopad 31 u2013 iopad 34 and iopad 41 u2013 iopad 44 respectively that is since the data corresponding to the first memory bank ba 11 of fig1 is stored in the first bank area comprising b 11 u2013 b 41 of each of the memory banks ba 21 u2013 ba 24 of fig2 the data is read written from in the four memory banks ba 21 u2013 ba 24 through the sixteen pads similarly the data corresponding to the other memory bank areas is read written from in the memory banks ba 21 u2013 ba 24 through the shared sixteen pads respectively a semiconductor memory device according to a preferred embodiment of the present invention disperses a plurality of i o pads at the surrounding areas of a plurality of.