Disclosed herein is an apparatus and a method for controlling a headlamp, and more particularly, an apparatus and a method for controlling a headlamp to perform a flashing function more efficiently while a vehicle is being driven. The apparatus includes, a rotating shield including a first shield protrusion portion which includes a plurality of protrusions formed in a direction of a rotation axis of a rotatable body and a second shield protrusion portion disposed on a side of the first shield protrusion portion; a sensor detecting a light distribution pattern of a vehicle based on a rotation angle of the rotating shield; and a rotating unit rotating the rotating shield at a predetermined angle toward the first or second shield protrusion portion, which forms the detected light distribution pattern, in order to perform a flashing function.