PURPOSE: To operate two charge pump circuits as a push-pull type basic bias pump by delaying an input signal used for pumping an electric charge stored in a substrate from a pumping capacitor and turning on a pumping transistor.

CONSTITUTION: Electric charge pumping circuits 22, 24 are provided in a circuit path from the input of a generator 14 to a substrate 20 and supply an electric charge to the substrate 20 responding to the level of an oscillating signal. Since these circuits have similar constitution, for example, the circuit 22 transfers the charge stored from a pumping capacitor 61 to the substrate 20 while a pumping transistor TR 50 does not make all threshold voltages of TR 50 a voltage loss. The conductive path of TR 50 is connected between the capacitor 61 and the substrate 20 as a serial circuit, the control gate electrode of TR 50 is connected in a bootstrap manner and TR 50 is turned on by delaying the input signal for pumping the charge to the substrate 20 from the capacitor 61.