Abstract: A power factor correction (PFC) controller and a power supply apparatus using the same are provided. The PFC controller includes a driving signal generation circuit and a zero-current prediction circuit. The driving signal generation circuit generates a driving signal to drive a power switch according to a control signal, where the power switch is switched in response to the driving signal, so as to convert an input voltage into an output voltage. The zero-current prediction circuit is coupled to the driving signal generation circuit and performs a capacitance charge/discharge operation, and thus obtains a charge/discharge time characteristic related to a zero-current timing. The zero-current prediction circuit generates the control signal to control operation of the driving signal generation circuit according to the charge/discharge time characteristic.