The present invention relates to an apparatus and a method for controlling auto focus of a camera module including a voice coil motor actuator. The camera module includes a sensing unit configured to sense a movement of the lens unit and a controller configured to control the movement of the lens unit based on a sensing signal sensed by the sensing unit. If an initial operation command is received, the controller moves the lens unit to an end point of a maximum movement range. If the lens unit is positioned at the end point of the maximum movement range, the controller compares the sensing signal sensed by the sensing unit with a predetermined reference signal to calculate a compensation value for an error. If a focus operation command is received, the controller can move the lens unit to a focus position based on the calculated compensation value and compensate for the focus position of the lens unit.