Sense amplifier and semiconductor memory device

PURPOSE: A sense amplifier and a semiconductor memory device are provided to prevent the deterioration of an island sensing margin by amplifying the data of a cell. CONSTITUTION: In a sense amplifier and a semiconductor memory device, a pull-up power supply unit(330) receives a pull-up power. A first inverter(311) has a positive bit line as an input while having negative bit line as an output. A second inverter(312) has a negative bit line as an input while having a positive bit line as an output. The first and second inverters receive pulled-up power through pulled-up power lines which are separated from each other.