A semiconductor memory device having a reduced noise interference is presented. The semiconductor memory device includes a first switch and a second switch. The first switch is disposed in a sub hole region or an edge region and is configured to be turned on in response to a first pre-control signal, which is enabled before a time point at which a sense amplifier array begins to operate, and to apply an external voltage to a first voltage line through which a bias voltage is supplied to the sense amplifier array. The second switch is configured to be turned on in response to a first control signal, which is enabled in a sense amplifier overdriving period, and to apply the external voltage to the first voltage line.