PURPOSE: To generate required voltage without loss by the threshold value voltage of a field-effect transistor provided on a final stage.

CONSTITUTION: The output signal Φ1 of an inverter 1 is raised to a grounded potential (GND) level or a power source voltage (VCC) level at a time t1. Although gate voltage 6g in a transistor 6 is raised to the VCC level by coupling through a capacitor 4, since the transistor 5 is conducted, the gate voltage becomes a voltage level Vthp. On the other hand, since the output signal Φ2 of an invertor 2 is fallen to the GND level from the VCC level, drain voltage 8d in the transistor 8 is fallen to a VCC level by coupling through the capacitor 3. Then, since a difference between the gate voltage 8g and the drain voltage 8d in the transistor 8 becomes Vthp-(--VCC), the transistor 8 is conducted, and charge is pulled out from a substrate. Since the transistor 6 is turned off corresponding to the gate voltage Vthp, the pulled out charge is held by the capacitor 3.