A control circuit module for a power factor corrector is provided to convert the operation mode of the inductor current from the boundary conduction mode (BCM) to the discontinuous conduction mode (DCM) when a transistor element is operated under the valley inductor current, thus reducing the switching frequency and increasing system efficiency, also to maintain the operation mode of the inductor current in the BCM when the transistor element is operated under the peak inductor current, thus maintaining system efficiency.