Abstract: In a level shifter for receiving a signal of a first voltage level and outputting a signal of a second voltage level, a pull-down driver pulls down a voltage level at an output terminal of the level shifter to a ground voltage level. A pull-up driver and an auxiliary pull-up device pull up the voltage level at the output terminal to the second voltage level. The level shifter can reduce leakage current and avoid operation delay of a device through the pull-up and pull-down drivers and that can implement a small-sized, lightweight and highly integrated semiconductor memory device.