A level shifter includes a resistor R1 connected to a power source, a MOSFET MN3 having a drain connected to the resistor R1 and a grounded source, a resistor R2 having the same resistance of the resistor R1 and connected to the power source, a MOSFET MN4 having a drain to the resistor R2 and a grounded source, a pulse generator 10 controlling ON/OFF of the MOSFETs MN3 and MN4 according to an input signal, a control part generating a set signal when the MOSFET MN3 is ON and a reset signal when the MOSFET MN4 is ON, a flip-flop that providing, according to the set and reset signals, an output signal level-shifted of the input signal to operate a switching element Q1, and a switching operation control part detecting when reference potential decreases to negative and stopping the switching element Q1.