A semiconductor integrated circuit having first and second power supply lines (Vcc,Vss) for receiving a power supply voltage, an external input terminal (84) for receiving an input signal, and a high voltage detection circuit (6) for detecting at the external input terminal a high voltage higher than a predetermined voltage which is higher than the power supply voltage. The high voltage detection circuit (6) comprises an input circuit (61) connected to the external input terminal (84) for generating a detection voltage; a reference voltage generating circuit (Q31-Q34) for generating a reference voltage; and a differential voltage amplifier (62) connected to receive the detection voltage and the reference voltage for amplifying the difference between the detection voltage and the reference voltage, to thereby determine whether the high voltage is applied. The input circuit comprises a level shift element (Q21-Q25) connected to the external input terminal (84) for providing the detection voltage; an impedance element (Q26-Q27) connected between the level shift element and the second power supply line (Vss); and a leak current compensating element (Q28,Q29) connected between the first power supply line (Vcc) and the level shift element for allowing a current to flow from the first power supply line through the leak current compensating element and the impedance element to the second power supply line when the high voltage is not applied to the external input terminal.