A register part of a mode register has a plurality of operation setting parts in which plural types of operating specifications are respectively set to operate the semiconductor memory. The mode register outputs a soft reset signal when at least a value of one-bit of the register part represents a reset state. A reset signal generator outputs a reset signal for resetting an internal circuit in response to the soft reset signal. In the present invention, a system that controls the semiconductor memory is required to necessarily assign a predetermined bit with a setting command of the mode register in order to generate the soft reset signal. Accordingly, it is possible to reliably reset the internal circuit by external control.