A sense amplifier driving line is connected to the source of an N-channel MOS transistor. Accordingly, even if a control signal attains H level, a sub-amplifier will not operate. This is because the sense amplifier driving line and an LIO line pair both attain a precharge potential, and a gate-source voltage of an N-channel MOS transistor attains 0V. Thus, it is not necessary to add a circuit configuration for supplying a signal notifying of activation of a row block, and a semiconductor memory device with a smaller area is obtained.