One embodiment includes a plurality of word lines, a plurality of source lines, a plurality of bit lines intersecting with the plurality of word lines, and a plurality of memory cells formed at intersections of the plurality of word lines and the plurality of bit lines. Each of the plurality of memory cells is a floating body cell. A gate of each floating body cell is connected to one of the word lines, a drain of each floating body cell is connected to one of the bit lines, and a source of each floating body cell is connected to one of the source lines. At least one bit line and source line selecting circuit is configured to selectively connect each of the plurality of bit lines to a first output bit line and to selectively connect the source lines to a source voltage. At least one sense amplifier is configured to sense data based on a voltage on the first output bit line.