A level converter includes a level conversion circuit, which is provided between a reference power supply line having a reference voltage level and a first power supply line coupled to a first power supply outputting a first voltage level, which inputs a first signal and outputs a second signal, the first signal having a first logic level and a second logic level, the second signal having a first logic level and a second logic level; a control signal generating circuit to output a control signal having the reference voltage level when a second power supply outputting the second voltage level is turned off and the first voltage level when the second power supply is turned on; and a coupling circuit to control an electrically connection between the first power supply line and an output node of the level conversion circuit based on the control signal.