A semiconductor device includes a pre-buffer for transferring a data signal on the basis of a first power supply voltage, a main buffer for amplifying and outputting the data signal transferred by the pre-buffer on the basis of a second power supply voltage different from the first power supply voltage, a switch unit for controlling a conductive state between the pre-buffer and the main buffer on the basis of a switch control signal, and a control circuit for generating the switch control signal for controlling the pre-buffer to set an output level of the pre-buffer to ground potential in accordance with transition of logical level of the switch control signal.