A semiconductor integrated circuit device is provided with first and second regions that are operated by mutually different voltages, and a signal wiring that supplies a signal from the first region to the second region. The second region includes a circuit that is connected to between a first wiring to which a voltage is selectively supplied and a third terminal to which a voltage is supplied, and is operated by a differential voltage between the voltage in the first wiring and the voltage supplied to the third terminal, and a discharge circuit for discharging a charge in the first wiring. By using the discharge circuit, the potential difference between the signal wiring and the first wiring is prevented from becoming larger, and thus makes it possible to reduce damages of the circuit included in the second region.