Semiconductor memory device with readily changeable memory capacity

A semiconductor memory device formed on a main surface of a semiconductor substrate, comprising first to sixth regions arranged on said main surface in a matrix of three rows and two columns, each region being formed in a quadrangle, said first to third regions being arranged in a first column, said fourth to sixth regions being arranged in a second column adjacent to said first to third regions, respectively,

• said first and third regions respectively including first and second memory cell arrays each formed in a quadrangle and having therein a plurality of memory cells arranged in rows and columns,
• said second region including a first sense amplifier band arranged between and shared by said first and second memory cell arrays, provided in a rectangle having first and second longer sides in contact with said first and second memory cell arrays, respectively,
• said fourth and sixth regions including first and second row decoders provided for said first and second memory cell arrays, respectively, to select a row of memory cells,
• said fifth region including a first column decoder selecting a column of said first and second memory cell arrays and a first sense amplifier control circuit outputting a control signal to said first sense amplifier band.