A semiconductor integrated circuit comprises a first MOS transistor connected at the drain to a power source terminal of a high potential power source and supplied at the gate with a predetermined voltage, a logic circuit including MOS transistors provided between the power source terminal and a circuit point at a potential and operating in a potential range between the high potential and the circuit point, and a circuit for making the potential at the circuit point coincide with the potential at the source of the first MOS transistor.