Disclosed herein are an apparatus and a method for controlling PWM switching frequency that employ a negate PWM scheme to thereby increase PWM switching frequency, improve control responsiveness, and reduce the size of the circuit. The apparatus includes: a power factor correction (PFC) converter configured to convert an AC voltage into a DC voltage, the converter comprising a transistor controlling an operation of the PFC converter and a current sensor for measuring an electric current flowing through the transistor; and a controller configured to receive an output from the current sensor and calculate a duty ratio of a switching signal applied to a gate terminal of the transistor. The controller applies the calculated duty ratio to the switching signal in an on-duty period of the switching signal.