A semiconductor memory apparatus includes: a first sense amplification unit including first and second inverters configured to be driven to voltage levels of a power driving signal and a ground driving signal and forming a latch structure between a bit line and a bit line bar; and a second sense amplification unit including first and second transistors configured to be driven to the voltage level of the ground driving signal and forming a latch structure between the bit line and the bit line bar when an activated switching signal is applied, wherein a threshold voltage of the second sense amplification unit is set lower than that of the first sense amplification unit.