PURPOSE: To obtain a charge pump circuit which operates effectively and securely, by providing two circuits which are driven by mutually out-of-phase current signals to a circuit which generates a prescribed potential difference between the 1st and the 2nd terminals by transferring charges from one terminal to the other.

CONSTITUTION: In a period 3, a capacitor C2 is charged by MOSTs M5 and M8 and at this time, the potential at a node E is lowered so that charges are supplied to a substrate from a capacitor C3 charged in the last period. In a period succeeding the period 3, reverse operation is performed in such a way that charges of the capacitor C2 charged in the period 3 are supplied to the substrate and the capacitor C3 is charged by MOSTs M9 and M12. Therefore, when the capacitor C2 or C3 is charged, the other capacitor supplies charges to the substrate and thus charges are supplied to the substrate nealy throughout the periods without reference to the time ratio between the periods 2 and 3. Consequently, the total amount of charge supplied to the substrate is increased and even if a current leaks to the substrate, the substrate potential is held low.