To provide a plurality of memory banks, each of which is divided into a plurality of segments; a bank address register that designates a memory bank that becomes a refresh target; a segment address register that designates a segment that becomes a refresh target; and a refresh control circuit that prohibits a refresh operation of the memory bank or the segment not designated by at least one of the bank address register and the segment address register. This semiconductor device is capable of designating whether to perform a refresh operation not only in a memory bank unit but also in a segment unit within the memory bank, and thus it achieves a further reduction of the power consumption.