Even-numbered columns are arranged in the first memory cell array (bank), and odd-numbered columns are arranged in the second memory cell array (bank). A column address signal is input to an adder through a buffer. When data is read out of two or more columns, the adder generates a column address signal whose address value is more than that of the column address signal by one. The adder supplies a first column decoder with a column address signal for addressing an even-numbered column and supplies a second column decoder with a column address signal for addressing an odd-numbered column. Since the even-numbered columns and odd-numbered columns are arranged in their separate memory cell arrays, data read out of continuous two or more columns do not collide with each other.